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A device is described for lifting catwalk grates comprising an elongated bent member with a handle at one end and a pair of notched braces and a hook at the opposite end that act in conjunction with each other to lock onto the grate and give mechanical advantage in lifting the grate. 10 figs.
Gunter, L.W.
A device for lifting catwalk grates comprising an elongated bent member with a handle at one end and a pair of notched braces and a hook at the opposite end that act in conjunction with each other to lock onto the grate and give mechanical advantage in lifting the grate.
Gunter, Larry W. (615 Sandpit Rd., Leesville, SC 29070)
Multilayer dielectric diffraction gratings
The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.
Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.
Multilayer dielectric diffraction gratings
The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.
Perry, Michael D. (Livermore, CA); Britten, Jerald A. (Oakley, CA); Nguyen, Hoang T. (Livermore, CA); Boyd, Robert (Livermore, CA); Shore, Bruce W. (Livermore, CA)
Reflective diffraction grating
Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.
Lamartine, Bruce C. (Los Alamos, NM)
Electrically-programmable diffraction grating
An electrically-programmable diffraction grating. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers).
Ricco, Antonio J. (Albuquerque, NM); Butler, Michael A. (Albuquerque, NM); Sinclair, Michael B. (Albuquerque, NM); Senturia, Stephen D. (Brookline, MA)
Electrically-programmable diffraction grating
An electrically-programmable diffraction grating is disclosed. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers). 14 figs.
Ricco, A.J.; Butler, M.A.; Sinclair, M.B.; Senturia, S.D.
Charged particle accelerator grating
A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.
Palmer, R.B.
Fiber Grating Environmental Sensing System
Fiber grating environmental measurement systems are comprised of sensors that are configured to respond to changes in moisture or chemical content of the surrounding medium through the action of coatings and plates inducing strain that is measured. These sensors can also be used to monitor the interior of bonds for degradation due to aging, cracking, or chemical attack. Means to multiplex these sensors at high speed and with high sensitivity can be accomplished by using spectral filters placed to correspond to each fiber grating environmental sensor. By forming networks of spectral elements and using wavelength division multiplexing arrays of fiber grating sensors may be processed in a single fiber line allowing distributed high sensitivity, high bandwidth fiber optic grating environmental sensor systems to be realized.
Schulz, Whitten L. (Fairview, OR); Udd, Eric (Fairview, OR)
Gratings Inc | Open Energy Information
Gratings Inc Gratings Inc Jump to: navigation, search Name Gratings, Inc. Place Albuquerque, New Mexico Zip 87107 Product R&D firm that specialises in microstructural and nanostructural approaches to different challenges facing the microelectronics and power industries. Coordinates 35.08418°, -106.648639° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":35.08418,"lon":-106.648639,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
MEMS tunable gratings with analog actuation
Science Conference Proceedings (OSTI)
We have designed and fabricated tunable gratings with period tunable to within fraction of a nanometer. We actuated the gratings by electrostatic and piezoelectric means, and demonstrated period changes of order 1 nm. Fabrication processes for the two ...
Wei-Chuan Shih; Chee Wei Wong; Yong Bae Jeon; Sang-Gook Kim; George Barbastathis
Gratings for High-Energy Petawatt Lasers
Science Conference Proceedings (OSTI)
To enable high-energy petawatt laser operation we have developed the processing methods and tooling that produced both the world's largest multilayer dielectric reflection grating and the world's highest laser damage resistant gratings. We have successfully delivered the first ever 80 cm aperture multilayer dielectric grating to LLNL's Titan Intense Short Pulse Laser Facility. We report on the design, fabrication and characterization of multilayer dielectric diffraction gratings.
Nguyen, H T; Britten, J A; Carlson, T C; Nissen, J D; Summers, L J; Hoaglan, C R; Aasen, M D; Peterson, J E; Jovanovic, I
Diffraction gratings used as identifying markers
A finely detailed defraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the defraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating.
Deason, Vance A. (Idaho Falls, ID); Ward, Michael B. (Idaho Falls, ID)
Embedded high-contrast distributed grating structures
A new class of fabrication methods for embedded distributed grating structures is claimed, together with optical devices which include such structures. These new methods are the only known approach to making defect-free high-dielectric contrast grating structures, which are smaller and more efficient than are conventional grating structures.
Zubrzycki, Walter J. (Albuquerque, NM); Vawter, Gregory A. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM)
Diffraction gratings used as identifying markers
A finely detailed diffraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the diffraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating. 7 figures.
Deason, V.A.; Ward, M.B.
Diffraction gratings used as identifying markers
A finely detailed defraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the defraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating. 7 figs.
Deason, V.A.; Ward, M.B.
Active diffraction gratings: Development and tests
Science Conference Proceedings (OSTI)
We present the realization and characterization of an active spherical diffraction grating with variable radius of curvature to be used in grazing-incidence monochromators. The device consists of a bimorph deformable mirror on the top of which a diffraction grating with laminar profile is realized by UV lithography. The experimental results show that the active grating can optimize the beam focalization of visible wavelengths through its rotation and focus accommodation.
Bonora, S.; Frassetto, F.; Poletto, L. [Institute of Photonics and Nanotechnologies, National Council for Research of Italy, via Trasea, 7, Padova 35131 (Italy); Zanchetta, E.; Della Giustina, G.; Brusatin, G. [Industrial Engineering Department, University of Padova, Via Marzolo 9, 35131 Padova (Italy)
ALS Scientists Patent Technique To Dramatically Advance Grating...
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ALS Scientists Patent Technique To Dramatically Advance Grating-Based Spectroscopy ALS Scientists Patent Technique To Dramatically Advance Grating-Based Spectroscopy Print Tuesday,...
Compact imaging spectrometer utilizing immersed gratings
A compact imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The imaging spectrometer comprises an entrance slit for transmitting light, means for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the means for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the means for receiving the light and the means for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light to the means for receiving the light, and the means for receiving the light directs the light to the detector array.
Chrisp, Michael P. (Danville, CA); Lerner, Scott A. (Corvallis, OR); Kuzmenko, Paul J. (Livermore, CA); Bennett, Charles L. (Livermore, CA)
Science Conference Proceedings (OSTI)
A novel fabrication method for soft x-ray transmission grating and other optical elements is presented. The method uses focused-ion-beam technology to fabricate high-quality free standing grating bars on transmission electron microscopy grids. High quality transmission gratings are obtained with superb accuracy and versatility. Using these gratings and back-illuminated CCD camera, absolutely calibrated x-ray spectra can be acquired for soft x-ray source diagnostics in the 100-3000 eV spectral range. Double grating combinations of identical or different parameters are easily fabricated, allowing advanced one-shot application of transmission grating spectroscopy. These applications include spectroscopy with different spectral resolutions, bandwidths, dynamic ranges, and may serve for identification of high-order contribution, and spectral calibrations of various x-ray optical elements.
Hurvitz, G.; Ehrlich, Y.; Shpilman, Z.; Levy, I.; Fraenkel, M. [Plasma Physics Department, Applied Physics Division, Soreq NRC, Yavne (Israel); Strum, G. [Solid State Department, Applied Physics Division, Soreq NRC, Yavne (Israel)
Grating enhanced solid-state laser amplifiers
A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. Such an invention, as disclosed herein, uses diffraction gratings to increase gain, stored energy density, and pumping efficiency of solid-state laser gain media, such as, but not limited to rods, disks and slabs. By coupling predetermined gratings to solid-state gain media, such as crystal or ceramic laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.
Erlandson, Alvin C. (Livermore, CA); Britten, Jerald A. (Clayton, CA)
Electro-optic Phase Grating Streak Spectrometer
The electro-optic phase grating streak spectrometer (EOPGSS) generates a time-resolved spectra equivalent to that obtained with a conventional spectrometer/streak camera combination, but without using a streak camera (by far the more expensive and problematic component of the conventional system). The EOPGSS is based on a phase, rather than an amplitude grating. Further, this grating is fabricated of electro-optic material such as, for example, KD*P, by either etching grooves into an E-O slab, or by depositing lines of the E-O material onto an optical flat. An electric field normal to the grating alters the material�s index of refraction and thus affects a shift (in angle) of the output spectrum. Ramping the voltage streaks the spectrum correspondingly. The streak and dispersion directions are the same, so a second (static, conventional) grating disperses the spectrum in the orthogonal direction to prevent different wavelengths from �overwriting� each other. Because the streaking is done by the grating, the streaked output spectrum is recorded with a time-integrating device, such as a CCD. System model, typical design, and performance expectations will be presented.
Goldin, F. J.
The fabrication of gratings including metal deposition processes for highly neutron absorbing lines is a critical issue to achieve a good visibility of the grating-based phase imaging system. The source grating for a neutron Talbot-Lau interferometer is an array of Gadolinium (Gd) structures that are generally made by sputtering, photo-lithography, and chemical wet etching. However, it is very challenging to fabricate a Gd structure with sufficient neutron attenuation of approximately more than 20 {mu}m using a conventional metal deposition method because of the slow Gd deposition rate, film stress, high material cost, and so on. In this article, we fabricated the source gratings for neutron Talbot-Lau interferometers by filling the silicon structure with Gadox particles. The new fabrication method allowed us a very stable and efficient way to achieve a much higher Gadox filled structure than a Gd film structure, and is even more suitable for thermal polychromatic neutrons, which are more difficult to stop than cold neutrons. The newly fabricated source gratings were tested at the polychromatic thermal neutron grating interferometer system of HANARO at the Korea Atomic Energy Research Institute, and the visibilities and images from the neutron phase imaging system with the new source gratings were compared with those fabricated by a Gd deposition method.
Kim, Jongyul [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Nuclear and Quantum Engineering Department, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Lee, Kye Hong; Lim, Chang Hwy; Kim, Taejoo [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Ahn, Chi Won [Nano Fusion Technology Division, National Nanofab Center, Daejeon 305-701 (Korea, Republic of); Cho, Gyuseong [Nuclear and Quantum Engineering Department, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Lee, Seung Wook [School of Mechanical Engineering, Pusan National University, Pusan 609-735 (Korea, Republic of)
Grate Furnace Combustion: A Submodel for the Solid Fuel Layer
Science Conference Proceedings (OSTI)
The reduction of NOx-formation in biomass fired grate furnaces requires the development of numerical models. To represent the variety in scales and physical processes playing a role in the conversion, newly developed ... Keywords: Grate furnace, biomass, reverse combustion
H. A. Kuijk; R. J. Bastiaans; J. A. Oijen; L. P. Goey
Integrated optical filters using Bragg gratings and resonators
This thesis provides an in-depth study of optical filters made using integrated Bragg gratings and Bragg resonators. Various topologies for making add/drop filters using integrated gratings are outlined. Each class of ...
Khan, Mohammad Jalal
Coupled-wave analysis of apodized volume gratings
gratings with finite size through numerical simula- tion", CLEO/IQEC and PhAST Technical Digest (Optical
Glebov, Leon
Superfluid {sup 4}He Quantum Interference Grating
Science Conference Proceedings (OSTI)
We report the first observation of quantum interference from a grating structure consisting of four weak link junctions in superfluid {sup 4}He. We find that an interference grating can be implemented successfully in a superfluid matter wave interferometer to enhance its sensitivity while trading away some of its dynamic range. We also show that this type of device can be used to measure absolute quantum mechanical phase differences. The results demonstrate the robust nature of superfluid phase coherence arising from quantum mechanics on a macroscopic scale.
Sato, Yuki; Joshi, Aditya; Packard, Richard [Physics Department, University of California, Berkeley, California 94720 (United States)
A New Multilayer-Based Grating for Hard X-ray Grating Interferometry |
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The Most Detailed Picture Yet of a Key AIDS Protein The Most Detailed Picture Yet of a Key AIDS Protein Superconductivity with Stripes How HIV Infects Cells Simulating Deep Earthquakes in the Laboratory A "Sponge" Path to Better Catalysts and Energy Materials Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed A New Multilayer-Based Grating for Hard X-ray Grating Interferometry November 20, 2013 Bookmark and Share An image of the phase shift in the mouse kidney from a Bonse-Hart interferometer built utilizing the new micro-multilayer grating provides a projection view of the blood vessels. A new kind of x-ray multilayer grating that could open a pathway for high-sensitivity, hard x-ray phase contrast full-field imaging of large
Fiber-bragg grating-loop ringdown method and apparatus
Science Conference Proceedings (OSTI)
A device comprising a fiber grating loop ringdown (FGLRD) system of analysis is disclosed. A fiber Bragg grating (FBG) or Long-Period grating (LPG) written in a section of single mode fused silica fiber is incorporated into a fiber loop. By utilizing the wing areas of the gratings' bandwidth as a wavelength dependent attenuator of the light transmission, a fiber grating loop ringdown concept is formed. One aspect of the present invention is temperature sensing, which has been demonstrated using the disclosed device. Temperature measurements in the areas of accuracy, stability, high temperature, and dynamic range are also described.
Wang, Chuji (Starkville, MS)
Fiber-bragg grating-loop ringdown method and apparatus
A device comprising a fiber grating loop ringdown (FGLRD) system of analysis is disclosed. A fiber Bragg grating (FBG) or Long-Period grating (LPG) written in a section of single mode fused silica fiber is incorporated into a fiber loop. By utilizing the wing areas of the gratings' bandwidth as a wavelength dependent attenuator of the light transmission, a fiber grating loop ringdown concept is formed. One aspect of the present invention is temperature sensing, which has been demonstrated using the disclosed device. Temperature measurements in the areas of accuracy, stability, high temperature, and dynamic range are also described.
Wang, Chuji (Starkville, MS)
Transmission Grating Measurements of Undulator K
This study was undertaken to understand the practicalities of determine K differences in the undulator modules by measuring single-shot x-ray spectra of the spontaneous radiation with a transmissive grating spectrometer under development to measure FEL spectra. Since the quality of the FEL is dependent on a uniform K value in all the undulator modules, being able to measure the relative undulator K values is important. Preliminary results were presented in a presentation, 'Use of FEL Off-Axis Zone Plate Spectrometer to Measure Relative K by the Pinhole/Centroid Method', at the 'LCLS Beam-Based Undulator K Measurements Workshop' on November 14, 2005 (UCRL-PRES-217281). This study applies equally well to reflective gratings of the appropriate period and inclinations.
Bionta, R. M.
Fluidized bed boiler having a segmented grate
A fluidized bed furnace (10) is provided having a perforate grate (9) within a housing which supports a bed of particulate material including some combustibles. The grate is divided into a plurality of segments (E2-E6, SH1-SH5, RH1-RH5), with the airflow to each segment being independently controlled. Some of the segments have evaporating surface imbedded in the particulate material above them, while other segments are below superheater surface or reheater surface. Some of the segments (E1, E7) have no surface above them, and there are ignitor combustors (32, 34) directed to fire into the segments, for fast startup of the furnace without causing damage to any heating surface.
Waryasz, Richard E. (Longmeadow, MA)
Compact reflective imaging spectrometer utilizing immersed gratings
A compact imaging spectrometer comprising an entrance slit for directing light, a first mirror that receives said light and reflects said light, an immersive diffraction grating that diffracts said light, a second mirror that focuses said light, and a detector array that receives said focused light. The compact imaging spectrometer can be utilized for remote sensing imaging spectrometers where size and weight are of primary importance.
Chrisp, Michael P. (Danville, CA)
Fiber optic security seal including plural Bragg gratings
An optical security system enables the integrity of a container seal to be remotely interrogated. A plurality of Bragg gratings is written holographically into the core of at least one optical fiber placed about the container seal, where each Bragg grating has a predetermined location and a known frequency for reflecting incident light. A time domain reflectometer is provided with a variable frequency light output that corresponds to the reflecting frequencies of the Bragg gratings to output a signal that is functionally related to the location and reflecting frequency of each of the Bragg gratings. 2 figs.
Forman, P.R.
Fiber optic security seal including plural Bragg gratings
An optical security system enables the integrity of a container seal to be remotely interrogated. A plurality of Bragg gratings is written holographically into the core of at least one optical fiber placed about the container seal, where each Bragg grating has a predetermined location and a known frequency for reflecting incident light. A time domain reflectometer is provided with a variable frequency light output that corresponds to the reflecting frequencies of the Bragg gratings to output a signal that is functionally related to the location and reflecting frequency of each of the Bragg gratings.
Forman, Peter R. (Los Alamos, NM)
ALS Scientists Patent Technique To Dramatically Advance Grating-Based
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ALS Scientists Patent Technique To ALS Scientists Patent Technique To Dramatically Advance Grating-Based Spectroscopy ALS Scientists Patent Technique To Dramatically Advance Grating-Based Spectroscopy Print Tuesday, 29 January 2013 16:28 Gratings - optical elements used to separate light in spectroscopy applications - have been in use since the early 19th century. Developments in the late 19th century led to the manufacture of gratings by highly precise ruling with a diamond onto a metallic surface. Many gratings are still produced today using the same technique. Holographic methods and ion etching are also used, but all of these techniques result in gratings that contain significant imperfections, which limits resolution. Watch a video about this topic... However, a new type of ultra-high diffraction grating recently patented by members of the ALS Experimental Systems Group (ESG), working with colleagues from Berkeley Lab's Center for X-ray Optics, stands to revolutionize the resolution capabilities of soft x-ray spectroscopy. The key to the new technique is the production of a near atomically perfect substrate, using the anisotropic etching of silicon.
ALS Scientists Patent Technique To Dramatically Advance Grating-Based
NLE Websites -- All DOE Office Websites (Extended Search)
ALS Scientists Patent Technique To Dramatically ALS Scientists Patent Technique To Dramatically Advance Grating-Based Spectroscopy ALS Scientists Patent Technique To Dramatically Advance Grating-Based Spectroscopy Print Gratings - optical elements used to separate light in spectroscopy applications - have been in use since the early 19th century. Developments in the late 19th century led to the manufacture of gratings by highly precise ruling with a diamond onto a metallic surface. Many gratings are still produced today using the same technique. Holographic methods and ion etching are also used, but all of these techniques result in gratings that contain significant imperfections, which limits resolution. Watch a video about this topic... However, a new type of ultra-high diffraction grating recently patented by members of the ALS Experimental Systems Group (ESG), working with colleagues from Berkeley Lab's Center for X-ray Optics, stands to revolutionize the resolution capabilities of soft x-ray spectroscopy. The key to the new technique is the production of a near atomically perfect substrate, using the anisotropic etching of silicon.
Grate assembly for fixed-bed coal gasifier
A grate assembly for a coal gasifier of a moving-bed or fixed-bed type is provided for crushing agglomerates of solid material such as clinkers, tailoring the radial distribution of reactant gases entering the gasification reaction zone, and control of the radial distribution of downwardly moving solid velocities in the gasification and combustion zone. The clinker crushing is provided by pinching clinkers between vertically oriented stationary bars and angled bars supported on the upper surface of a rotating conical grate. The distribution of the reactant gases is provided by the selective positioning of horizontally oriented passageways extending through the grate. The radial distribution of the solids is provided by mounting a vertically and generally radially extending scoop mechanism on the upper surface of the grate near the apex thereof.
Notestein, John E. (Morgantown, WV)
Grate assembly for fixed-bed coal gasifier
A grate assembly for a coal gasifier of a moving-bed or fixed-bed type is provided for crushing agglomerates of solid material such as clinkers, tailoring the radial distribution of reactant gases entering the gasification reaction zone, and control of the radial distribution of downwardly moving solid velocities in the gasification and combustion zone. The clinker crushing is provided by pinching clinkers between vertically oriented stationary bars and angled bars supported on the upper surface of a rotating conical grate. The distribution of the reactant gases is provided by the selective positioning of horizontally oriented passageways extending through the grate. The radial distribution of the solids is provided by mounting a vertically and generally radially extending scoop mechanism on the upper surface of the grate near the apex thereof.
Notestein, J.E.
Compact Refractive Imaging Spectrometer Designs Utilizing Immersed Gratings
A compact imaging spectrometer comprising an entrance slit for directing light, a first means for receiving the light and focusing the light, an immersed diffraction grating that receives the light from the first means and defracts the light, a second means for receiving the light from the immersed diffraction grating and focusing the light, and an image plane that receives the light from the second means
Lerner, Scott A. (Livermore, CA); Bennett, Charles L. (Livermore, CA); Bixler, Jay V. (Oakland, CA); Kuzmenko, Paul J. (Livermore, CA); Lewis, Isabella T. (San Jose, CA)
Town Known for First Thanksgiving Grateful for Energy Savings | Department
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Town Known for First Thanksgiving Grateful for Energy Savings Town Known for First Thanksgiving Grateful for Energy Savings Town Known for First Thanksgiving Grateful for Energy Savings November 22, 2011 - 3:55pm Addthis Since January, when energy efficiency improvements were made to Memorial Hall, the civic center for the Plymouth, Mass., community, the building's energy savings have been nearly $1,200 per month. | Photo courtesy of the city of Plymouth. Since January, when energy efficiency improvements were made to Memorial Hall, the civic center for the Plymouth, Mass., community, the building's energy savings have been nearly $1,200 per month. | Photo courtesy of the city of Plymouth. Chris Galm Marketing & Communications Specialist, Office of Energy Efficiency & Renewable Energy What does this project do?
Kinetic analysis of two dimensional metallic grating Cerenkov maser
Science Conference Proceedings (OSTI)
The dispersion relation of two dimensional metallic grating Cerenkov maser has been given by using kinetic analysis, in which the influence of electron movement is directly considered without using an equivalent dielectric medium assumption. The effects of structural parameters and beam state on the interaction gain and synchronous frequency have also been investigated in detail by numerical calculations. To an illustrative case, the quantitative relations produced from varying the gap distance between electron beam and metallic grating, beam current, electron transverse to axial velocity ratio, and electron axial velocity spread have been obtained. The developed method can be used to predict the real interaction system performances.
Zhao Ding [Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China)
Controlled angular redirection of light via nanoimprinted disordered gratings
, the daylighting effect vanishes as the system becomes equivalent to an omnidirectional diffuser and transparency (Van Nostrand Reinhold, 1986). 19. M. Kischkoweit-Lopin, "An overview of daylighting systems," Sol gratings are presented in the context of improved interior daylighting and may furthermore be suited
arXiv.org help - Why Submit the TeX/LaTeX Source?
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abshep-th9511053). TeX source is more compact and space-efficient. Frequent Red Herring Concerns: Will the auto-TeXing embed figures? Yes. Our TeX installation can do...
Science Conference Proceedings (OSTI)
We evaluate a new transmission grating spectrometer for standoff laser-induced breakdown spectroscopy (LIBS) measurements. LIBS spectra collected from standoff distances are often weak, with smaller peaks blending into the background and noise. Scattered light inside the spectrometer can also contribute to poor signal-to-background and signal-to-noise ratios for smaller emission peaks. Further, collecting standoff spectra can be difficult because most spectrometers are designed for laboratory environments and not for measurements in the field. To address these issues, a custom-designed small, lightweight transmission grating spectrometer with no moving parts was built that is well suited for standoff LIBS field measurements. The performance of the spectrometer was quantified through 10 m standoff LIBS measurements collected from aluminum alloy samples and measurements from spectra of a Hg-Ar lamp. The measurements were compared to those collected using a Czerny-Turner reflective grating spectrometer that covered a similar spectral range and used the same ICCD camera. Measurements using the transmission grating spectrometer had a 363% improved signal-to-noise ratio when measured using the 669 nm aluminum emission peak.
Weisberg, Arel; Craparo, Joseph; De Saro, Robert; Pawluczyk, Romuald
Phase-shifting point diffraction interferometer grating designs
In a phase-shifting point diffraction interferometer, by sending the zeroth-order diffraction to the reference pinhole of the mask and the first-order diffraction to the test beam window of the mask, the test and reference beam intensities can be balanced and the fringe contrast improved. Additionally, using a duty cycle of the diffraction grating other than 50%, the fringe contrast can also be improved.
Naulleau, Patrick (Oakland, CA); Goldberg, Kenneth Alan (Berkeley, CA); Tejnil, Edita (San Carlos, CA)
Sensitivity in X-ray grating interferometry on compact systems
The optimization of compact X-ray grating interferometry systems is crucial for the progress of this technique in industrial devices. Here, an analytical formulation for the sensitivity of the phase contrast image acquisition is derived using previous results from noise analyses. Furthermore, experimental measurements of the sensitivity for different configurations are compared, providing further insight into the dependence on polychromatic radiation. Finally, strategies for the geometrical optimization are given.
Thuering, Thomas; Modregger, Peter; Haemmerle, Stefan; Weiss, Stephan; Nueesch, Joachim; Stampanoni, Marco [Swiss Light Source, Paul Scherrer Institut, Villigen PSI (Switzerland) and Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Zurich (Switzerland); School of Biology and Medicine, University of Lausanne, Lausanne (Switzerland); SCANCO Medical AG, Bruettisellen (Switzerland)
High temperature metallic diffraction gratings and process of manufacturing same
This invention is comprised of a method of applying diffraction gratings or images directly to the surface of a substrate wherein the gratings or images are capable of withstanding high temperatures, pressures, humidity and other such conditions related to materials testing. The method includes coating the surface of the substrate with an uniform layer of metal which is then overlaid with a layer of photo-resist material. Next, after contacting the photo-resist material with a master image containing regions of opacity and transparency, electromagnetic radiation is directed through the master image to expose the photo-resist material such that a contact print of the master image is produced on the photo-resist material. Then, after removing the master image, the photo-resist material is developed so as to remove unhardened portions thereof and leave corresponding portions of the metal layer uncovered. Finally, after removing or etching the uncovered portions of the metal layer, the remaining photo-resist material is removed to produce a metallic diffraction grating or image of predetermined size and pattern on the surface of the substrate.
Deason, V.A.; Hsu, Karen M.; Miller, R.L.
A tunable nanomechanical near-field grating is disclosed which is capable of varying the intensity of a diffraction mode of an optical output signal. The tunable nanomechanical near-field grating includes two sub-gratings each having line-elements with width and thickness less than the operating wavelength of light with which the grating interacts. Lateral apertures in the two sub-gratings are formed from the space between one line-element of the first sub-grating and at least one line-element of the second sub-grating. One of the sub-gratings is capable of motion such that at least one of aperture width and aperture depth changes, causing a perturbation to the near-field intensity distribution of the tunable nanomechanical near-field grating and a corresponding change to the far-field emission of thereof.
Carr, Dustin Wade (Albuquerque, NM); Bogart, Gregory Robert (Corrales, NM)
Compact Reflective Imaging Spectrometer Design Utilizing An Immersed Grating And Anamorphic Mirror
A compact imaging spectrometer comprising an entrance slit, an anamorphic mirror, a grating, and a detector array. The entrance slit directs light to the anamorphic mirror. The anamorphic mirror receives the light and directs the light to the grating. The grating receives the light from the anamorphic mirror and defracts the light back onto the anamorphic mirror. The anamorphic mirror focuses the light onto a detector array.
Lerner, Scott A. (Corvalis, OR)
The authors investigate light absorption in organic solar cells in which indium tin oxide (ITO) is replaced by a new metallic architecture (grating) as a transparent electrode. Different from typical metal nanowire gratings, our gratings consist of metal nanowalls with nanoscale footprint and (sub)microscale height [Adv. Mater. 23, 2469 (2011)], thus ensuring high optical transmittance and electrical conductivity. Simulations reveal that a broadband and polarization-insensitive light absorption enhancement is achieved via two mechanisms, when such silver nanowall gratings are employed in P3HT:PCBM based solar cells. Overall absorption enhanced by ~23% compared to a reference cell with ITO electrode.
Ye, Zhuo; Chaudhary, Sumit; Kuang, Ping; Ho, Kai-Ming
Development of pulse laser processing for mounting fiber Bragg grating
Pulse laser processing has been developed for the application of industrial plants in monitoring and maintenance. Surface cleaning by nano-second laser ablation was demonstrated for decontamination of oxide layers of Cr contained steel. Direct writing by femtosecond processing induced a Bragg grating in optical fiber to make it a seismic sensor for structural health monitoring. Adhesive cement was used to fix the seismic sensor on the surface of reactor coolant pipe material. Pulse laser processing and its related technologies were presented to overcome the severe accidents of nuclear power plants.
Nishimura, Aikihko; Shimada, Yukihiro; Yonemoto, Yukihiro; Suzuki, Hirokazu; Ishibashi, Hisayoshi [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umebidai Kidugawa Kyoto 619-0215 (Japan); Applied Laser Technology Institute, Tsuruga Head Office, Japan Atomic Energy Agency, 65-20 Kizaki Tsuruga Fukui 914-8585 (Japan); Technical Research and Development Institute, Kumagai Gumi Co., Ltd., 2-1 Tsukudo, Shinjuku Tokyo 162-8557 (Japan)
TE Connectivity Finds Answers in Tomography
NLE Websites -- All DOE Office Websites (Extended Search)
TE Connectivity Finds Answers in TE Connectivity Finds Answers in Tomography TE Connectivity Finds Answers in Tomography Print Thursday, 22 August 2013 10:50 TE Connectivity is a world leader in connectivity-the $13 billion global company designs and manufactures more than 500,000 different electronic connectivity products for the automotive, energy, industrial, broadband communications, consumer device, healthcare, aerospace, and defense industries. TE Connectivity has a long-standing commitment to innovation and engineering excellence. Their products help address challenges arising from companies' need for energy efficiency, always-on communications, and ever-increasing productivity. Recently, a team led by TE's senior manager of materials development, Dr. Jerzy Gazda (at left), has been investigating how ALS tomography capabilities can help the company develop more efficient connectors.
Recycling of CdTe photovoltaic waste
A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate and electrolyzing the leachate to separate Cd from Te, wherein the Te is deposits onto a cathode while the Cd remains in solution.
Goozner, Robert E. (Charlotte, NC); Long, Mark O. (Charlotte, NC); Drinkard, Jr., William F. (Charlotte, NC)
Interferometric hard x-ray phase contrast imaging at 204 nm grating period
We report on hard x-ray phase contrast imaging experiments using a grating interferometer of approximately 1/10th the grating period achieved in previous studies. We designed the gratings as a staircase array of multilayer stacks which are fabricated in a single thin film deposition process. We performed the experiments at 19 keV x-ray energy and 0.8 {mu}m pixel resolution. The small grating period resulted in clear separation of different diffraction orders and multiple images on the detector. A slitted beam was used to remove overlap of the images from the different diffraction orders. The phase contrast images showed detailed features as small as 10 {mu}m, and demonstrated the feasibility of high resolution x-ray phase contrast imaging with nanometer scale gratings.
Wen Han; Gomella, Andrew A.; Miao, Houxun; Lynch, Susanna K. [Imaging Physic Laboratory, Biophysics and Biochemistry Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892 (United States); Wolfe, Douglas E. [Applied Research Laboratory, Penn State University, State College, Pennsylvania 16804 (United States); Xiao Xianghui; Liu Chian [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Morgan, Nicole [National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892 (United States)
Grating Based, Phase Contrast Radiography with Bremsstrahlung Source
Phase-contrast radiography (PCR) generates an image from gradients in the phase of the probing X-radiation induced by the radiographic object, and can therefore make visible features difficult or impossible to see with conventional, absorption-contrast (ACR) radiography. For any particular object, variations in either the real or imaginary parts of the index of refraction could be greater. Most practical difficulties of PCR arise from the very small deviation from unity (~10-5-10-6, depending of material and energy) of the real part of the index of refraction. In principal, straightforward shadowgraphy would provide a phase-contrast image, but in practice this is usually overwhelmed by the zero-order (bright field) signal. Eliminating this sets the phase-contrast signal against a dark field (as in Schlieren photography with visible light). One way to do this with X-rays is with a grating that produces a Talbot interference pattern. Minute variations in optical path lengths through the radiographic object can significantly shift the Talbot fringes, and these shifts constitute a dark-field signal separate from the zero-order wave. This technique has recently been investigated up to ~20keV [1-3]; this work addresses what sets the practical upper limit, and where that limit is. These appear to be grating fabrication, and ~60keV, respectively.
Fletcher Goldin and Shaun Hampton
High efficiency multilayer blazed gratings for EUV and soft X-rays: Recent developments
Science Conference Proceedings (OSTI)
Multilayer coated blazed gratings with high groove density are the best candidates for use in high resolution EUV and soft x-ray spectroscopy. Theoretical analysis shows that such a grating can be potentially optimized for high dispersion and spectral resolution in a desired high diffraction order without significant loss of diffraction efficiency. In order to realize this potential, the grating fabrication process should provide a perfect triangular groove profile and an extremely smooth surface of the blazed facets. Here we report on recent progress achieved at the Advanced Light Source (ALS) in fabrication of high quality multilayer coated blazed gratings. The blazed gratings were fabricated using scanning beam interference lithography followed by wet anisotropic etching of silicon. A 200 nm period grating coated with a Mo/Si multilayer composed with 30 bi-layers demonstrated an absolute efficiency of 37.6percent in the 3rd diffraction order at 13.6 nm wavelength. The groove profile of the grating was thoroughly characterized with atomic force microscopy before and after the multilayer deposition. The obtained metrology data were used for simulation of the grating efficiency with the vector electromagnetic PCGrate-6.1 code. The simulations showed that smoothing of the grating profile during the multilayer deposition is the main reason for efficiency losses compared to the theoretical maximum. Investigation of the grating with cross-sectional transmission electron microscopy revealed a complex evolution of the groove profile in the course of the multilayer deposition. Impact of the shadowing and smoothing processes on growth of the multilayer on the surface of the sawtooth substrate is discussed.
Voronov, Dmitriy; Ahn, Minseung; Anderson, Erik; Cambie, Rossana; Chang, Chih-Hao; Goray, Leonid; Gullikson, Eric; Heilmann, Ralf; Salmassi, Farhad; Schattenburg, Mark; Warwick, Tony; Yashchuk, Valeriy; Padmore, Howard
Fabrication and characterization of a new high density Sc/Si multilayer sliced grating
State of the art soft x-ray spectroscopy techniques like Resonant Inelastic X-ray Scattering (RIXS) require diffraction gratings which can provide extremely high spectral resolution of 105-106. This problem may be addressed with a sliced multilayer grating with an ultra-high groove density (up to 50,000 mm-1) proposed in the recent publication [Voronov, D. L., Cambie, R., Feshchenko, R. M., Gullikson, E., Padmore, H. A., Vinogradov, A. V., Yashchuk, V. V., Proc. SPIE 6705, 67050E (2007)]. It has been suggested to fabricate such a grating by deposition of a soft x-ray multilayer on a substrate which is a blazed saw-tooth grating (echellette) with low groove density. Subsequent polishing applied to the coated grating removes part of the coating and forms an oblique-cut multiline structure that is a sliced multilayer grating. The resulting grating has a short-scale periodicity of lines (bilayers), which is defined by the multilayer period and the oblique-cut angle. We fabricated and tested a Sc/Si multilayer sliced grating suitable for EUV applications, which is a first prototype based on the suggested technique. In order to fabricate an echellette substrate, we used anisotropic KOH etching of a Si wafer. The etching regime was optimized to obtain smooth and flat echellette facets. A Sc/Si multilayer was deposited by dc-magnetron sputtering, and after that it was mechanically polished using a number of diamond pastes. The resulting sliced grating prototype with ~;;270 nm line period has demonstrated a dispersive ability in the 41-49 nm photon wavelength range with a diffraction efficiency of ~;;7percent for the optimized 38th order assigned to the echellette grating of 10 mu m period.
Advanced Light Source; Voronov, Dmitriy L.; Cambie, Rossana; Gullikson, Eric; Yashchuk, Valeriy; Padmore, Howard; Pershin, Yuri; Ponomarenko, Alexander; Kondratenko, Valeriy
Response of Cds/CdTe Devices to Te Exposure of Back Contact: Preprint
Theoretical predictions of thin-film CdS/CdTe photovoltaic (PV) devices have suggested performance may be improved by reducing recombination due to Te-vacancy (VTe) or Te-interstitial (Tei) defects. Although formation of these intrinsic defects is likely influenced by CdTe deposition parameters, it also may be coupled to formation of beneficial cadmium vacancy (VCd) defects. If this is true, reducing potential effects of VTe or Tei may be difficult without also reducing the density of VCd. In contrast, post-deposition processes can sometimes afford a greater degree of defect control. Here we explore a post-deposition process that appears to influence the Te-related defects in polycrystalline CdTe. Specifically, we have exposed the CdTe surface to Te prior to ZnTe:Cu/Ti contact-interface formation with the goal of reducing VTe but without significantly reducing VCd. Initial results show that when this modified contact is used on a CdCl2-treated CdS/CdTe device, significantly poorer device performance results. This suggests two things: First, the amount of free-Te available during contact formation (either from chemical etching or CuTe or ZnTe deposition) may be a more important parameter to device performance than previously appreciated. Second, if processes have been used to reduce the effect of VTe (e.g., oxygen and chlorine additions to the CdTe), adding even a small amount of Te may produce detrimental defects.
Gessert, T. A.; Burst, J. M.; Ma, J.; Wei, S. H.; Kuciauskas, D.; Barnes, T. M.; Duenow, J. N.; Young, M. R.; Rance, W. L.; Li, J. V.; Dippo, P.
Particulate Contacts to Si and CdTe: Al, Ag, Hg-Cu-Te, and Sb-Te
Our team has been investigating the use of particle-based contacts in both Si and CdTe solar cell technologies. First, in the area of contacts to Si, powders of Al and Ag prepared by an electroexplosion process have been characterized by transmission electron microscopy (TEM), TEM elemental determination X-ray spectroscopy (TEM-EDS), and TEM electron diffraction (TEM-ED). These Al and Ag particles were slurried and tested as contacts to p- and n-type silicon wafers, respectively. Linear current-voltage (I-V) was observed for Ag on n-type Si, indicative of an ohmic contact, whereas the Al on p-type Si sample was non-ideal. A wet-chemical surface treatment was performed on one Al sample and TEM-EDS indicated a substantial decrease in the O contaminant level. The treated Al on p-type Si films exhibited linear I-V after annealing. Second, in the area of contacts to CdTe, particles of Hg-Cu-Te and Sb-Te have been applied as contacts to CdTe/CdS/SnO2 heterostructures prepared by the standard NREL protocol. First, Hg-Cu-Te and Sb-Te were prepared by a metathesis reaction. After CdCl2 treatment and NP etch of the CdTe layer, particle contacts were applied. The Hg-Cu-Te contacted cells exhibited good electrical characteristics, with Voc > 810 mV and efficiencies > 11.5 % for most cells. Although Voc > 800 mV were observed for the Sb-Te contacted cells, efficiencies in these devices were limited to 9.1%, presumably by a large series resistance (>20 {Omega}) observed in all samples.
Schulz, D. L.; Ribelin, D.; Curtis, C. J.; Ginley, D. S.
Nanomechanical near-field grating apparatus and acceleration sensor formed therefrom
A nanomechanical near-field grating device is disclosed which includes two sub-gratings vertically spaced by a distance less than or equal to an operating wavelength. Each sub-grating includes a plurality of line-elements spaced apart by a distance less than or equal to the operating wavelength. A light source (e.g., a VCSEL or LED) can provide light at the operating wavelength for operation of the device. The device can operate as an active grating, with the intensity of a reflected or transmitted portion of the light varying as the relative positions of the sub-gratings are controlled by an actuator. The device can also operate as a passive grating, with the relative positions of the sub-gratings changing in response to an environmentally-induced force due to acceleration, impact, shock, vibration, gravity, etc. Since the device can be adapted to sense an acceleration that is directed laterally or vertically, a plurality of devices can be located on a common substrate to form a multi-axis acceleration sensor.
Carr, Dustin Wade (Albuquerque, NM); Bogart, Gregory Robert (Corrales, NM); Keeler, Bianca E. N. (Albuquerque, NM)
Synthesis of Nanowires-enhanced Bulk TE Nanocomposite for High ...
Science Conference Proceedings (OSTI)
Abstract Scope, There are great interest in developing high-efficiency thermoelectrical (TE) materials for power generation. Significant improvements in a few TE�...
TGCat : THE CHANDRA TRANSMISSION GRATING DATA CATALOG AND ARCHIVE
The Chandra Transmission Grating Data Archive and Catalog (TGCat) provides easy access to analysis-ready products, specifically, high-resolution X-ray count spectra and their corresponding calibrations. The web interface makes it easy to find observations of a particular object, type of object, or type of observation; to quickly assess the quality and potential usefulness of the spectra from pre-computed summary plots; or to customize a view with an interactive plotter, optionally combining spectra over multiple orders or observations. Data and responses can be downloaded as a package or as individual files, and the query results themselves can be retrieved as ASCII or Virtual Observatory tables. Portable reprocessing scripts used to create the archive and which use the Chandra X-ray Center's (CXC's) software and other publicly available software are also available, facilitating standard or customized reprocessing from Level 1 CXC archival data to spectra and responses with minimal user interaction.
Huenemoerder, David P.; Dewey, Daniel; Nowak, Michael A.; Schulz, Norbert S.; Davis, John E.; Houck, John C.; Marshall, Herman L.; Noble, Michael S.; Canizares, Claude R. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Mitschang, Arik; Nichols, Joy S.; Morgan, Doug [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
CdSxTe1-x Alloying in CdS/CdTe Solar Cells
A CdSxTe1-x layer forms by interdiffusion of CdS and CdTe during the fabrication of thin-film CdTe photovoltaic (PV) devices. The CdSxTe1-x layer is thought to be important because it relieves strain at the CdS/CdTe interface that would otherwise exist due to the 10% lattice mismatch between these two materials. Our previous work [1] has indicated that the electrical junction is located in this interdiffused CdSxTe1-x region. Further understanding, however, is essential to predict the role of this CdSxTe1-x layer in the operation of CdS/CdTe devices. In this study, CdSxTe1-x alloy films were deposited by RF magnetron sputtering and co-evaporation from CdTe and CdS sources. Both radio-frequency-magnetron-sputtered and co-evaporated CdSxTe1-x films of lower S content (x<0.3) have a cubic zincblende (ZB) structure akin to CdTe, while those of higher S content have a hexagonal wurtzite (WZ) structure like that of CdS. Films become less preferentially oriented as a result of a CdCl2 heat treatment at ~400 degrees C for 5 min. Films sputtered in a 1% O2/Ar ambient are amorphous as deposited, but show CdTe ZB, CdS WZ, and CdTe oxide phases after a CdCl2 heat treatment (HT). Films sputtered in O2 partial pressure have a much wider bandgap (BG) than expected. This may be explained by nanocrystalline size effects seen previously [2] for sputtered oxygenated CdS (CdS:O) films.
Duenow, J. N.; Dhere, R. G.; Moutinho, H. R.; To, B.; Pankow, J. W.; Kuciauskas, D.; Gessert, T. A.
Science Conference Proceedings (OSTI)
Multilayer dielectric (MLD) diffraction gratings for Petawatt-class laser systems possess unique laser damage characteristics. Details of the shape of the grating lines and the concentration of absorbing impurities on the surface of the grating structures both have strong effects on laser damage threshold. It is known that electric field enhancement in the solid material comprising the grating lines varies directly with the linewidth and inversely with the line height for equivalent diffraction efficiency. Here, they present an overview of laser damage characteristics of MLD gratings, and describe a process for post-processing ion-beam etched grating lines using very dilute buffered hydrofluoric acid solutions. This process acts simultaneously to reduce grating linewidth and remove surface contaminants, thereby improving laser damage thresholds through two pathways.
Nguyen, H T; Larson, C C; Britten, J A
Grating light reflection spectroscopy (GLRS) is an emerging technique for spectroscopic analysis and sensing. A transmission diffraction grating is placed in contact with the sample to be analyzed, and an incident light beam is directed onto the grating. At certain angles of incidence, some of the diffracted orders are transformed from traveling waves to evanescent waves. This occurs at a specific wavelength that is a function of the grating period and the complex index of refraction of the sample. The intensities of diffracted orders are also dependent on the sample's complex index of refraction. The authors describe the use of GLRS, in combination with electrochemical modulation of the grating, for the detection of trace amounts of aromatic hydrocarbons. The diffraction grating consisted of chromium lines on a fused silica substrate. The depth of the grating lines was 1 {micro}m, the grating period was 1 {micro}m, and the duty cycle was 50%. Since chromium was not suitable for electrochemical modulation of the analyte concentration, a 200 nm gold layer was deposited over the entire grating. This gold layer slightly degraded the transmission of the grating, but provided satisfactory optical transparency for the spectroelectrochemical experiments. The grating was configured as the working electrode in an electrochemical cell containing water plus trace amounts of the aromatic hydrocarbon analytes. The grating was then electrochemically modulated via cyclic voltammetry waveforms, and the normalized intensity of the zero order reflection was simultaneously measured. The authors discuss the lower limits of detection (LLD) for two analytes, 7-dimethylamino-1,2-benzophenoxazine (Meldola's Blue dye) and 2,4,6-trinitrotoluene (TNT), probed with an incident HeNe laser beam ({lambda} = 543.5 nm) at an incident angle of 52.5{degree}. The LLD for 7-dimethylamino-1,2-benzophenoxazine is approximately 50 parts per billion (ppb), while the LLD for TNT is approximately 50 parts per million (ppm). The possible factors contributing to the differences in LLD for these analytes are discussed. This is the final report for a Sandia National Laboratories Laboratory Directed Research and Development (LDRD) project conducted during fiscal years 1998 and 1999 (case number 3518.190).
Double-{beta}-decay Q values of {sup 130}Te, {sup 128}Te, and {sup 120}Te
The double-{beta}-decay Q values of {sup 130}Te, {sup 128}Te, and {sup 120}Te have been determined from parent-daughter mass differences measured with the Canadian Penning Trap mass spectrometer. The {sup 132}Xe-{sup 129}Xe mass difference, which is precisely known, was also determined to confirm the accuracy of these results. The {sup 130}Te Q value was found to be 2527.01{+-}0.32 keV, which is 3.3 keV lower than the 2003 Atomic Mass Evaluation recommended value and is consistent with another recent Penning trap measurement. The {sup 128}Te and {sup 120}Te Q values were found to be 865.87{+-}1.31 and 1714.81{+-}1.25 keV, respectively. For {sup 120}Te, this reduction in uncertainty of nearly a factor of 8 opens up the possibility of using this isotope for sensitive searches for neutrinoless double-electron capture and electron capture with {beta}{sup +}emission.
Scielzo, N. D. [Physical Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Caldwell, S.; Savard, G.; Sternberg, M.; Van Schelt, J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Clark, J. A.; Levand, A. F.; Sun, T. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Deibel, C. M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute of Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Fallis, J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Gulick, S. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Lascar, D. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States); Li, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Mintz, J. [Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States); Norman, E. B. [Physical Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States); Sharma, K. S. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)
A grateful dead analysis: the relationship between concert and listening behavior
Science Conference Proceedings (OSTI)
The Grateful Dead was an American band born out of the 1960s San Francisco, California psychedelic movement, that played music together from 1965 to 1995. Despite relatively little popular radio airtime, while on tour the Grateful Dead enjoyed a cult-like following from a fan base that numbered in the millions. Still today, some ten years after dissolution, the band remains popular according to online music services, such as last.fm. This article presents a comparative analysis between 1,590 of the Grateful Dead's live concert set lists from 1972 to 1995 and 2,616,990 Grateful Dead listening events by last.fm users from August 2005 to October 2007. While there is a strong correlation between how songs were played in concert and how they were listened to by last.fm members, the outlying songs in this trend identify interesting aspects of the band and their present-day fans.
Rodriguez, Marko A [Los Alamos National Laboratory; Gintautas, Vadas [Los Alamos National Laboratory; Pepe, Alberto [U.OF CA AT LA
Recycling of CdTe photovoltaic waste
A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the metals in dilute nitric acid, leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate, adding a calcium containing base to the leachate to precipitate Cd and Te, separating the precipitated Cd and Te from the leachate, and recovering the calcium-containing base.
Goozner, Robert E. (Charlotte, NC); Long, Mark O. (Charlotte, NC); Drinkard, Jr., William F. (Charlotte, NC)
Recycling of CdTe photovoltaic waste
A method for extracting and reclaiming metals from scrap CdTe photovoltaic cells and manufacturing waste by leaching the metals in dilute nitric acid, leaching the waste with a leaching solution comprising nitric acid and water, skimming any plastic material from the top of the leaching solution, separating the glass substrate from the liquid leachate, adding a calcium containing base to the leachate to precipitate Cd and Te, separating the precipitated Cd and Te from the leachate, and recovering the calcium-containing base. 3 figs.
Goozner, R.E.; Long, M.O.; Drinkard, W.F. Jr.
Elimination of higher-order diffraction using zigzag transmission grating in soft x-ray region
Science Conference Proceedings (OSTI)
We present a realization of the sinusoidal transmission function using a series of zigzag-profiled strips where the transmission takes on the binary values 0 and 1 in a two-dimensional distribution. A zigzag transmission grating of 1000 line/mm has been fabricated and demonstrated on the soft x-ray beam of synchrotron radiation. The axial single-order diffraction indicates that the zigzag transmission grating is adequate for spectroscopic application.
Zang, H. P.; Wang, C. K. [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Gao, Y. L.; Zhou, W. M.; Kuang, L. Y.; Wei, L.; Fan, W.; Zhang, W. H.; Zhao, Z. Q.; Cao, L. F.; Gu, Y. Q.; Zhang, B. H. [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Jiang, G. [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Zhu, X. L.; Xie, C. Q. [Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China); Zhao, Y. D.; Cui, M. Q. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
IMPROVEMENT OF CdMnTe DETECTOR PERFORMANCE BY MnTe PURIFICATION
Science Conference Proceedings (OSTI)
Residual impurities in manganese (Mn) are a big obstacle to obtaining high-performance CdMnTe (CMT) X-ray and gamma-ray detectors. Generally, the zone-refining method is an effective way to improve the material's purity. In this work, we purified the MnTe compounds combining the zone-refining method with molten Te, which has a very high solubility for most impurities. We confirmed the improved purity of the material by glow-discharge mass spectrometry (GDMS). We also found that CMT crystals from a multiply-refined MnTe source, grown by the vertical Bridgman method, yielded better performing detectors.
Kim, K.H.; Bolotnikov, A.E.; Camarda, G.S.; Tappero, R.; Hossain, A.; Cui, Y.; Yang, G.; Gul, R.; and James, R.B.
Thermodynamic and Transport Properties of YTe3, LaTe3 and CeTe3
Measurements of heat capacity, susceptibility, and electrical resistivity are presented for single crystals of the charge density wave compounds YTe{sub 3}, LaTe{sub 3}, and CeTe{sub 3}. The materials are metallic to low temperatures, but have a small density of states due to the charge density wave gapping large portions of the Fermi surface. CeTe{sub 3} is found to be a weak Kondo lattice, with an antiferromagnetic ground state and T{sub N} = 2.8 K. The electrical resistivity of all three compounds is highly anisotropic, confirming the weak dispersion perpendicular to Te planes predicted by band structure calculations.
Ru, N.
Science Conference Proceedings (OSTI)
Acid Value and Free Amine Value of Fatty Quaternary Ammonium Chlorides AOCS Official Method Te 3a-64 Methods Downloads Methods Downloads DEFINITION The acid value is the mg of potassium hydroxide necessary to neut
Perspective on TeV-scale physics
Science Conference Proceedings (OSTI)
These lectures review theoretical motivations and experimental prospects for the study of TeV-scale physics. Three clues to the importance of TeV physics are discussed: implications of quantum corrections for the masses of a fourth generation quark-lepton family, the gauge hierarchy problem and known solutions, and implications of symmetry and unitarity for the symmetry-breaking sector of the electroweak gauge theory. The experimental prospects are reviewed with emphasis on the multi-TeV pp colliders that may be built in the 1990's. The topics include new phenomena that might occur - e.g., a fourth generation, heavy gauge bosons, composite structure, and supersymmetry - as well as the signals of the unknown SU(2)/sub L/ /times/ U(1)/sub Y/ breaking mechanism that must occur within the TeV domain. 96 refs., 21 figs.
Chanowitz, M.S.
Science Conference Proceedings (OSTI)
Acid Value AOCS Official Method Te 4a-70 Methods Downloads Methods Downloads DEFINITION The acid value is the mg of potassium hydroxide necessary to neutralize the free acids in 1 g of test sample.
Science Conference Proceedings (OSTI)
LaTeX PAPER TMS1, Jane Doe2, John Doe2 1TMS (The Minerals Metals & Materials Society)184 Thorn Hill Rd.; Warrendale, PA 15086-7514, USA 2Name of�...
Science Conference Proceedings (OSTI)
Acid Value AOCS Official Method Te 1a-64 Methods Downloads Methods Downloads DEFINITION The acid value is the mg of potassium hydroxide necessary to neutralize fatty acids in 1 g of test sample. SCO
Science Conference Proceedings (OSTI)
Color, Photometric Index AOCS Official Method Te 2a-64 Methods Downloads Methods Downloads DEFINITION This method measures the color of commercial fatty acids and expresses the color as percent transmission at 440
GaTe semiconductor for radiation detection
GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.
Payne, Stephen A. (Castro Valley, CA); Burger, Arnold (Nashville, TN); Mandal, Krishna C. (Ashland, MA)
The TE Wave Transmission Method for Electron Cloud Measurements at Cesr-TA
CBP-836 THE TE WAVE TRANSMISSION METHOD FOR ELECTRON CLOUDobtained using the TE transmission technique described inBesides the TE transmission method in its initial
Desantis, S.
INTEGRAL observations of TeV plerions
Amongst the sources seen in very high gamma-rays several are associated with Pulsar Wind Nebulae (``TeV plerions''). The study of hard X-ray/soft gamma-ray emission is providing an important insight into the energetic particle population present in these objects. The unpulsed emission from pulsar/pulsar wind nebula systems in the energy range accessible to the INTEGRAL satellite is mainly synchrotron emission from energetic and fast cooling electrons close to their acceleration site. Our analyses of public INTEGRAL data of known TeV plerions detected by ground based Cherenkov telescopes indicate a deeper link between these TeV plerions and INTEGRAL detected pulsar wind nebulae. The newly discovered TeV plerion in the northern wing of the Kookaburra region (G313.3+0.6 powered by the middle aged PSR J1420-6048) is found to have a previously unknown INTEGRAL counterpart which is besides the Vela pulsar the only middle aged pulsar detected with INTEGRAL. We do not find an INTEGRAL counterpart of the TeV plerion associated with the X-ray PWN ``Rabbit'' G313.3+0.1 which is possibly powered by a young pulsar.
A. I. D. Hoffmann; D. Horns; A. Santangelo
Impurity Gettering Effect of Te Inclusions in Cdznte Single Crystals
Science Conference Proceedings (OSTI)
The local impurity distribution in Te inclusions of CdZnTe (CZT) crystal was investigated by the time-of-flight secondary ion mass spectrometry (Tof-SIMS) technique. Direct evidence of impurity gettering in Te inclusions has been observed for the first time. The impurity gettering in Te inclusions originated from the diffusion mechanism during crystal growth and segregation mechanism during crystal cooling. This phenomenon is meaningful, because it reveals how Te inclusions affect CZT properties and provides a possible approach to reduce the impurities in CZT by the way of removing Te inclusions.
Yang, G.; Bolotnikov, A; Cui, Y; Camarda, G; Hossain, A; James, R
Acceleration of non-relativistic electrons at a dielectric grating structure: Status report
Science Conference Proceedings (OSTI)
We report on an experiment aiming at a proof-of-concept of a non-relativistic direct laser accelerator. The system is based on a fused-silica transmission grating illuminated by Titanium:sapphire femtosecond pulses in order to excite evanescent spatial modes, which propagate synchronously with 28 keV electrons originating from an electron column of a scanning electron microscope. The grating period is 750 nm, and we use the third spatial harmonic to continuously accelerate the non-relativistic electrons. With a laser pulse energy of about 150 nJ numerical simulations show expected accelerating gradients of up to 60 MeV/m and an energy gain of around 300 eV at a distance of 100 nm away from the grating surface. The current status of the experiment is reported.
Breuer, John; Hommelhoff, Peter [Max Planck Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching (Germany)
Dual transmission grating based imaging radiometer for tokamak edge and divertor plasmas
Science Conference Proceedings (OSTI)
The designs of single transmission grating based extreme ultraviolet (XUV) and vacuum ultraviolet (VUV) imaging spectrometers can be adapted to build an imaging radiometer for simultaneous measurement of both spectral ranges. This paper describes the design of such an imaging radiometer with dual transmission gratings. The radiometer will have an XUV coverage of 20-200 A with a {approx}10 A resolution and a VUV coverage of 200-2000 A with a {approx}50 A resolution. The radiometer is designed to have a spatial view of 16 Degree-Sign , with a 0.33 Degree-Sign resolution and a time resolution of {approx}10 ms. The applications for such a radiometer include spatially resolved impurity monitoring and electron temperature measurements in the tokamak edge and the divertor. As a proof of principle, the single grating instruments were used to diagnose a low temperature reflex discharge and the relevant data is also included in this paper.
Kumar, Deepak; Clayton, Daniel J.; Parman, Matthew; Stutman, Dan; Tritz, Kevin; Finkenthal, Michael [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)
Production of Gratings for High-Energy Petawatt-Class Lasers
Science Conference Proceedings (OSTI)
At the time of this writing, we have manufactured and delivered more than 25 multilayer dielectric diffraction gratings from 470-800 mm in long aperture for pulse compression on Petawatt-class,1-micron laser systems being built at government and university facilities in the U.S and elsewhere. We present statistics of diffraction efficiency and its spatial uniformity, diffracted wavefront, and laser damage results on witness gratings. We also discuss yield, failure modes, and manufacturing improvements necessary to improve upon the current state of the art.
Nguyen, H T; Carlson, T C; Hoaglan, C R; Nissen, J D; Aasen, M D; Peterson, J E; Jovanovic, I; Brewer, S W; Britten, J A
Science Conference Proceedings (OSTI)
In recent years, X-ray imaging based on the differential phase contrast gained more and more attention to be used in X-ray imaging. Among other techniques like crystal-based diffraction and propagation methods, the grating based Talbot interferometry offers an approach measuring phase modulations of X-rays while passing low absorbing objects. The Talbot interferometer yields for highly efficient X-ray imaging signals for hard X-rays with energies above 10 keV. One factor with high impact on the imaging performance of such grating interferometers is the gratings quality. We introduce a fabrication process allowing both, the fabrication of phase modulating and analyzer gratings with high aspect ratios, up to 100. Structural deviations from the optimal geometry of the gratings are investigated and their influence on the obtained image quality is discussed.
Kenntner, Johannes; Altapova, Venera; Grund, Thomas; Pantenburg, Franz Josef; Meiser, Jan; Baumbach, Tilo; Mohr, Juergen [Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology (IMT), 76021 Karlsruhe (Germany); Karlsruhe Institute of Technology (KIT), Laboratory for Application of Synchrotron Radiation, 76128 Karlsruhe (Germany); Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology (IMT), 76021 Karlsruhe (Germany); Karlsruhe Institute of Technology (KIT), Laboratory for Application of Synchrotron Radiation, 76128 Karlsruhe (Germany); Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology (IMT), 76021 Karlsruhe (Germany)
Search for ? + / EC double beta decay of 120 Te
Science Conference Proceedings (OSTI)
We present a search for ? + / EC double beta decay of 120 Te performed with the CUORICINO experiment
C. Tomei; The CUORICINO Collaboration
We report on measurements of the diffraction efficiency of 200-nm-period freestanding blazed transmission gratings for wavelengths in the 0.96 to 19.4 nm range. These critical-angle transmission (CAT) gratings achieve highly efficient blazing over a broad band via total external reflection off the sidewalls of smooth, tens of nanometer thin ultrahigh aspect-ratio silicon grating bars and thus combine the advantages of blazed x-ray reflection gratings with those of more conventional x-ray transmission gratings. Prototype gratings with maximum depths of 3.2 and 6 {mu}m were investigated at two different blaze angles. In these initial CAT gratings the grating bars are monolithically connected to a cross support mesh that only leaves less than half of the grating area unobstructed. Because of our initial fabrication approach, the support mesh bars feature a strongly trapezoidal cross section that leads to varying CAT grating depths and partial absorption of diffracted orders. While theory predicts broadband absolute diffraction efficiencies as high as 60% for ideal CAT gratings without a support mesh, experimental results show efficiencies in the range of {approx}50-100% of theoretical predictions when taking the effects of the support mesh into account. Future minimization of the support mesh therefore promises broadband CAT grating absolute diffraction efficiencies of 50% or higher.
Heilmann, Ralf K.; Ahn, Minseung; Bruccoleri, Alex; Chang, Chih-Hao; Gullikson, Eric M.; Mukherjee, Pran; Schattenburg, Mark L.
Novel Method for Growing Te-Inclusion-Free CZT
Science Conference Proceedings (OSTI)
The authors propose a new method for growth of detector-grade CdZnTe (CZT) with reduced concentration and sizes of Te inclusions. The method is designed to impede the formation of Te-rich inclusions in crystals due to the use of new CZT growth method and a unique ampoule design.
ZnO-ZnTe Nanocone Heterojunctions
Science Conference Proceedings (OSTI)
Semiconductor nanostructure heterojunctions are expected to be efficient structures for next-generation photovoltaic solar cells, radiation detectors, and light-emitting diodes. In this letter we report heterojunctions made of vertically aligned ZnO/ZnTe nanocones synthesized using a combination of thermal vapor deposition and pulsed-laser deposition (PLD). The ZnO nanocones and nanorods were synthesized as cores by utilizing the growth rate difference between central and boundary sites of precursor domains during thermal vapor deposition. The p-n heterojunctions were subsequently formed by growing ZnTe as shells on the nanocone surface using PLD. The ZnTe shells were polycrystalline structures, while ZnO cores were wurzite structures. The p-n junction of the nanocone core-shell structure exhibited I-V characteristics consistent with a p-n diode, but the nanorod junction did not. These structural and electric characteristics indicate that the ZnO nanocones are more feasible than ZnO nanorods as heterojunctions because the sloping facets of the nanocones facilitate deposition of ZnTe by PLD without the deleterious effects of shadowing. Furthermore, based on theoretical modeling of nanostructure heterojunctions, the nanocone-based junction exhibits an electrostatic potential profile that is much more effective for carrier transport than the electrostatic potential for the nanorod-based junction.
Lee, Sang Hyun [ORNL; Smith, Barton [ORNL; Zhang, Xiaoguang [ORNL; Seo, Sung Seok A [ORNL; Bell, Zane W [ORNL; Xu, Jun [ORNL
Mechanism of terahertz photoconductivity in semimetallic HgTe/CdHgTe quantum wells
Science Conference Proceedings (OSTI)
Terahertz photoconductivity in magnetic fields in semimetallic HgTe/CdHgTe quantum wells has been studied. The main contribution to photoconductivity comes from a signal that appears as a result of electron-gas heating. It is shown that, with the cyclotron resonance conditions satisfied, the photoconductivity signal is composed of cyclotron-resonance and bolometric components. However, in this case too, the bolometric contribution predominates.
Vasilyev, Yu. B., E-mail: firstname.lastname@example.com [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Mikhailov, N. N. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Gouider, F. [Institut fuer Angewandte Physik (Germany); Vasilyeva, G. Yu. [St. Petersburg State Polytechnic University (Russian Federation); Nachtwei, G. [Institut fuer Angewandte Physik (Germany)
THE PERFORMANCE OF THIN FILM SOLAR CELLS EMPLOYING PHOTOVOLTAIC Cu22014x Te-CdTe HETEROJUNCTIONS (1)
195 THE PERFORMANCE OF THIN FILM SOLAR CELLS EMPLOYING PHOTOVOLTAIC Cu22014x Te This paper is a short status report on the continuing development of Cu22014xTe-CdTe thin film solar cells thin film work. The most pressing current need is to determine how to extend cell life, particularly
Paris-Sud XI, Université de
Picosecond polarization-selective transient grating experiments in sodium-seeded flames
techniques such as coherent anti-Stokes Raman scattering (CARS) ,2V3laser induced fluorescence (LIF),4 the laser beams (CARS and FWM), of a different frequency than some or all of the laser beams (LIF, CARS) Electric field picture for one fringe of an intensity grating. The electric field amplitude varies
Fayer, Michael D.
Improved grating and bar cell models in cortical area V1 and texture coding
Science Conference Proceedings (OSTI)
This paper presents improved models of cortical neurons in V1 that act like grating and bar detectors. Both models use the same frontend, which consists of a contrast normalisation in combination with isotropic DOG filtering, followed by anisotropic ... Keywords: Computational models, Cortical cells, Diatoms, Groupings, Symmetry order, Texture analysis
J. M. H. du Buf
X-ray Grating Interferometry at ESRF: Applications and Recent Technical Developments
We report on the implementation of X-ray grating interferometry at the imaging beamline ID19 of the European Synchrotron Radiation Facility (ESRF). We give a brief overview of the results obtained so far with this instrument and on ongoing developments.
Weitkamp, T. [Synchrotron Soleil, Gif-sur-Yvette (France); Zanette, I.; Bernard, P.; Valade, J.-P.; Baruchel, J. [European Synchrotron Radiation Facility (ESRF), Grenoble (France); Schulz, G.; Lang, S.; Deyhle, H.; Mueller, B. [Biomaterials Science Center, University of Basel, Basel (Switzerland); Bech, M.; Tapfer, A.; Pfeiffer, F. [Physik-Department E17, Technische Universitaet Muenchen, Muenchen (Germany); Rutishauser, S.; Donath, T.; David, C. [Labor fuer Mikro- und Nanotechnologie, Paul Scherrer Institut (PSI), Villigen (Switzerland); Reznikova, E.; Kenntner, J.; Mohr, J. [Institut fuer Mikrostrukturtechnik, Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany)
In-Situ Continuous Detonation Velocity Measurements Using Fiber-optic Bragg Grating Sensors
Science Conference Proceedings (OSTI)
In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation and detonation research requires continuous measurement of low order detonation velocities as the detonation runs up to full order detonation for a given density and initiation pressure pulse. A novel detector of detonation velocity is presented using a 125 micron diameter optical fiber with an integral chirped fiber Bragg grating as an intrinsic sensor. This fiber is embedded in the explosive under study and interrogated during detonation as the fiber Bragg grating scatters light back along the fiber to a photodiode, producing a return signal dependant on the convolution integral of the grating reflection bandpass, the ASE intensity profile and the photodetector response curve. Detonation velocity is measured as the decrease in reflected light exiting the fiber as the grating is consumed when the detonation reaction zone proceeds along the fiber sensor axis. This small fiber probe causes minimal perturbation to the detonation wave and can measure detonation velocities along path lengths tens of millimeters long. Experimental details of the associated equipment and preliminary data in the form of continuous detonation velocity records within nitromethane and PBX-9502 are presented.
Benterou, J; Udd, E; Wilkins, P; Roeske, F; Roos, E; Jackson, D
Preferential orientation of Te precipitates in melt-grown CZT
Science Conference Proceedings (OSTI)
Cadmium zinc telluride (Cd1-xZnxTe or CZT) has proved to be a useful material for semiconductor gamma-ray spectrometers and other electro-optic devices. It is often grown Te-rich to optimize its electrical characteristics, but this off-stoichiometric growth leads to the formation of semimetallic Te precipitates in the semiconducting host crystal. These precipitates can impair device performance and their formation needs to be inhibited, if possible, during growth. Characterization of melt-grown CZT has shown that Te precipitates are often faceted. In this study, characterization of several particles of different shapes revealed that most of the Te precipitates were preferentially oriented with the {101}CZT||{-12-10}Te . A secondary orientation relationship was also observed as {11-1}CZT||{01-11}Te for one of the {111}CZT family of planes. One of the particles exhibited {110}CZT||{01-10}Te and {001}CZT||{0001}Te . Precipitates were often found on {111}CZT twin boundaries and, in these cases, it was possible to assign specific orientations with respect to the twin plane. The expected orientation of the {0001}-plane of Te aligned with the {111}-plane of CZT was not observed even though a good lattice match is predicted in ab initio models. Observations of strained and polycrystalline Te precipitates are also discussed with relevance to the ab initio model and to impacts on electronic properties.
Henager, Charles H.; Edwards, Danny J.; Schemer-Kohrn, Alan L.; Bliss, Mary; Jaffe, John E.
CdTe PV: Real and Perceived EHS Risks
As CdTe photovoltaics reached commercialization, questions have been raised about potential cadmium emissions from CdTe PV modules. Some have attacked the CdTe PV technology as unavoidably polluting the environment, and made comparisons of hypothetical emissions from PV modules to cadmium emissions from coal fired power plants. This paper gives an overview of the technical issues pertinent to these questions and further explores the potential of EHS risks during production, use and decommissioning of CdTe PV modules. The following issues are discussed: (a) The physical and toxicological properties of CdTe, (b) comparisons of Cd use in CdTe PV with its use in other technologies and products, and the (c) the possibility of CdTe releases from PV modules.
Fthenakis, V.; Zweibel, K.
This conference paper describes the spectroscopic cathodoluminescence (CL), electron-beam induced current (EBIC), and capacitance-Voltage (C-V) measurements are used to study the formation of CdS/CdTe devices processed using ion-beam milling and a ZnTe:Cu/Ti contact. Results show heating in vacuum at {approx}360 C and ion-beam milling lead to observable changes in the CL emission from the CdCl2-treated CdTe surface. Changes in the CL spectrum are also observed as ZnTe:Cu layer thickness increases. These changes are correlated to published studies of defect levels and shown to be due, possibly, to an n-type region existing between the ZnTe:Cu contact interface and the p-CdTe layers. This n-type region is eliminated once a sufficiently thick ZnTe:Cu layer is produced.
Gessert, T. A.; Romero, M. J.; Johnston, S.; Keyes, B.; Dippo, P.
We experimentally demonstrate graphene-plasmon polariton excitation in a continuous graphene monolayer resting on a two-dimensional subwavelength silicon grating. The subwavelength silicon grating is fabricated by a nanosphere lithography technique with a self-assembled nanosphere array as a template. Measured transmission spectra illustrate the excitation of graphene-plasmon polaritons, which is further supported by numerical simulations and theoretical prediction of plasmonband diagrams. Our grating-assisted coupling to graphene-plasmon polaritons forms an important platform for graphene-based opto-electronics applications.
Zhu, Xiaolong; Jepsen, Peter Uhd; Hansen, Ole; Mortensen, N Asger; Xiao, Sanshui
ASE Suppression in a Diode-Pumped Nd:YLF Regenerative Amplifier Using a Volume Bragg Grating
Science Conference Proceedings (OSTI)
Instrument-limited suppression of out-of-band amplified spontaneous emission (ASE) is demonstrated for the first time in a Nd:YLF diode-pumped regenerative amplifier using a volume Bragg grating (VBG) as a cavity mirror.
Okishev, A.V.; Dorrer, C.; Smirnov, V.I.; Glebov, L.B.; Zuegel, J.D.
This thesis describes the design and analysis of a system for patterning large-area gratings with nanometer level phase distortions. The novel patterning method, termed scanning beam interference lithography (SBIL), uses ...
Konkola, Paul Thomas, 1973-
CdZnTe technology for gamma ray detectors
Science Conference Proceedings (OSTI)
CdZnTe detector technology has been developed at NASA Goddard for imaging and spectroscopy applications in hard x-ray and gamma ray astronomy. A CdZnTe strip detector array with capabilities for arc second imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. CdZnTe detectors also have applications for medical imaging
Carl Stahle; Jack Shi; Peter Shu; Scott Barthelmy; Ann Parsons; Steve Snodgrass
Fiber Bragg Grating Sensors R&D for Nuclear Power Applications
Science Conference Proceedings (OSTI)
Fiber-optic sensors offer a broad range of advantages over traditional electrical sensors. These advantages include electromagnetic immunity, significantly lower signal transmission loss, high signal transfer rate (or wide operating spectrum), and better multiplexing capability. Among the many types of fiber-optic sensors, fiber Bragg grating (FBG) sensors stand out because of their simple mechanical structure, ease of compliance with industrial standards, simple multiplexing, and adaptable manufacturing...
Liquidus Projection of Thermoelectric Ag-Sn-Te Ternary System
Science Conference Proceedings (OSTI)
Presentation Title, Liquidus Projection of Thermoelectric Ag-Sn-Te Ternary ... Ag Decorated Al Nanoparticles as Novel Ink Materials for Printed Electronics�...
A technique for precise measurement of the modulation transfer function (MTF), suitable for characterization of a broad class of surface profilometers, is investigated in detail. The technique suggested in [Proc. SPIE 7077-7, (2007), Opt. Eng. 47(7), 073602-1-5 (2008)]is based on use of binary pseudo-random (BPR) gratings and arrays as standard MTF test surfaces. Unlike most conventional test surfaces, BPR gratings and arrays possess white-noise-like inherent power spectral densities (PSD), allowing the direct determination of the one- and two-dimensional MTF, respectively, with a sensitivity uniform over the entire spatial frequency range of a profiler. In the cited work, a one dimensional realization of the suggested method based on use of BPR gratings has been demonstrated. Here, a high-confidence of the MTF calibration technique is demonstrated via cross comparison measurements of a number of two dimensional BPR arrays using two different interferometric microscopes and a scatterometer. We also present the results of application of the experimentally determined MTF correction to the measurement taken with the MicromapTM-570 interferometric microscope of the surface roughness of a super-polished test mirror. In this particular case, without accounting for the instrumental MTF, the surface rms roughness over half of the instrumental spatial frequency bandwidth would be underestimated by a factor of approximately 1.4.
Barber, Samuel K.; Anderson, Erik D.; Cambie, Rossana; McKinney, Wayne R.; Takacs, Peter Z.; Stover, John C.; Voronov, Dmitriy L.; Yashchuk, Valeriy V.
X-ray luminescence of CdTe quantum dots in LaF{sub 3}:Ce/CdTe nanocomposites
Science Conference Proceedings (OSTI)
CdTe quantum dots have intense photoluminescence but exhibit almost no x-ray luminescence. However, intense x-ray luminescence from CdTe quantum dots is observed in LaF{sub 3}:Ce/CdTe nanocomposites. This enhancement in the x-ray luminescence of CdTe quantum dots is attributed to the energy transfer from LaF{sub 3}:Ce to CdTe quantum dots in the nanocomposites. The combination of LaF{sub 3}:Ce nanoparticles and CdTe quantum dots makes LaF{sub 3}:Ce/CdTe nanocomposites promising scintillators for radiation detection.
Hossu, Marius; Liu Zhongxin; Yao Mingzhen; Ma Lun; Chen Wei
CdS/CdTe Solar Cells Containing Directly Deposited CdSxTe1-x Alloy Layers: Preprint
A CdSxTe1-x layer forms by interdiffusion of CdS and CdTe during the fabrication of thin-film CdTe photovoltaic (PV) devices. The CdSxTe1-x layer is thought to be important because it relieves strain at the CdS/CdTe interface that would otherwise exist due to the 10% lattice mismatch between these two materials. Our previous work [1] has indicated that the electrical junction is located in this interdiffused CdSxTe1-x region. Further understanding, however, is essential to predict the role of this CdSxTe1-x layer in the operation of CdS/CdTe devices. In this study, CdSxTe1-x alloy films were deposited by radio-frequency (RF) magnetron sputtering and co-evaporation from CdTe and CdS sources. Both RF-magnetron-sputtered and co-evaporated CdSxTe1-x films of lower S content (x<0.3) have a cubic zincblende (ZB) structure akin to CdTe, whereas those of higher S content have a hexagonal wurtzite (WZ) structure like that of CdS. Films become less preferentially oriented as a result of a CdCl2 heat treatment (HT) at ~400 degrees C for 5 min. Films sputtered in a 1% O2/Ar ambient are amorphous as deposited, but show CdTe ZB, CdS WZ, and CdTe oxide phases after a CdCl2 HT. Films sputtered in O2 partial pressure have a much wider bandgap than expected. This may be explained by nanocrystalline size effects seen previously [2] for sputtered oxygenated CdS (CdS:O) films. Initial PV device results show that the introduction of a directly-deposited CdSxTe1-x alloy layer into the device structure produces devices of comparable performance to those without the alloy layer when a CdCl2 HT is performed. Further investigation is required to determine whether the CdCl2 heat treatment step can be altered or eliminated through direct deposition of the alloy layer.
Duenow, J. N.; Dhere, R. G.; Moutinho, H. R.; To, B.; Pankow, J. W.; Kuciauskas, D.; Gessert, T. A.
Excited quark production at a 100 TeV VLHC
I look for a dijet resonance produced by an excited quark q* in a simulated sample corresponding to 3 ab^{-1} of pp collisions at $\\sqrt{s} = 100$ TeV. Using a cut and count analysis approach I demonstrate the potential to explore q* masses up to 50 TeV, corresponding to a length scale of around 4 am.
Jacob Anderson
Excited quark production at a 100 TeV VLHC
I look for a dijet resonance produced by an excited quark q* in a simulated sample corresponding to 3 ab^{-1} of pp collisions at $\\sqrt{s} = 100$ TeV. Using a cut and count analysis approach I am able to explore q* masses up to 50 TeV, corresponding to a length scale of around 4 am.
Anderson, Jacob
Micro-Raman spectroscopy has been applied to investigate the impact of laser irradiation on semiconducting CdTe/ZnTe quantum dots (QDs) structures. A reference sample (without dots) was also studied for comparison. Both samples were grown by molecular beam epitaxy technique on the p-type GaAs substrate. The Raman spectra have been recorded for different time of a laser exposure and for various laser powers. The spectra for both samples exhibit peak related to the localized longitudinal (LO) ZnTe phonon of a wavenumber equal to 210 cm{sup -1}. For the QD sample, a broad band corresponding to the LO CdTe phonon related to the QD-layer appears at a wavenumber of 160 cm{sup -1}. With increasing time of a laser beam exposure and laser power, the spectra get dominated by tellurium-related peaks appearing at wavenumbers around 120 cm{sup -1} and 140 cm{sup -1}. Simultaneously, the ZnTe surface undergoes rising damage, with the formation of Te aggregates at the pinhole edge as reveal atomic force microscopy observations. Local temperature of irradiated region has been estimated from the anti-Stokes/Stokes ratio of the Te modes intensity and it was found to be close or exceeding ZnTe melting point. Thus, the laser damage can be explained by the ablation process.
Zielony, E.; Placzek-Popko, E.; Henrykowski, A.; Gumienny, Z.; Kamyczek, P.; Jacak, J. [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Nowakowski, P.; Karczewski, G. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland)
Use of separate ZnTe interface layers to form OHMIC contacts to p-CdTe films
A method of improving electrical contact to a thin film of a p-type tellurium-containing II-VI semiconductor comprising: depositing a first undoped layer of ZnTe on a thin film of p-type tellurium containing II-VI semiconductor with material properties selected to limit the formation of potential barriers at the interface between the p-CdTe and the undoped layer, to a thickness sufficient to control diffusion of the metallic-doped ZnTe into the p-type tellurim-containing II-VI semiconductor, but thin enough to minimize affects of series resistance; depositing a second heavy doped p-type ZnTe layer to the first layer using an appropriate dopant; and depositing an appropriate metal onto the outer-most surface of the doped ZnTe layer for connecting an external electrical conductor to an ohmic contact.
Gessert, Timothy A. (Conifer, CO)
Effects of Te inclusions on the performance of CdZnTe radiation detectors
Science Conference Proceedings (OSTI)
Te inclusions existing at high concentrations in CdZnTe (CZT) material can degrade the performance of CZT detectors. These microscopic defects trap the free electrons generated by incident radiation, so entailing significant fluctuations in the total collected charge and thereby strongly affecting the energy resolution of thick (long-drift) detectors. Such effects were demonstrated in thin planar detectors, and, in many cases, they proved to be the dominant cause of the low performance of thick detectors, wherein the fluctuations in the charge losses accumulate along the charge's drift path. We continued studying this effect using different tools and techniques. We employed a dedicated beamline recently established at BNL's National Synchrotron Light Source for characterizing semiconductor radiation detectors, along with an IR transmission microscope system, the combination of which allowed us to correlate the concentration of defects with the devices performances. We present here our new results from testing over 50 CZT samples grown by different techniques. Our goals are to establish tolerable limits on the size and concentrations of these detrimental Te inclusions in CZT material, and to provide feedback to crystal growers to reduce their numbers in the material.
Bolotnikov,A.E.; Abdul-Jabber, N. M.; Babalola, O. S.; Camarda, G. S.; Cui, Y.; Hossain, A. M.; Jackson, E. M.; Jackson, H. C.; James, J. A.; Kohman, K. T.; Luryi, A. L.; James, R. B.
Dynamics of Jacobi's elliptic spatial waves in a nonlinear optical grating
Science Conference Proceedings (OSTI)
This paper presents the results of our study on the dynamics of Jacobi's elliptic spatial waves in a nonlinear optical grating based on a generalized coupled-mode model. We discuss the characteristics of their amplitudes, widths, and spatial periods as well as their bifurcation in the associated phase plane. Our study on the dynamical propagation of perturbed profiles reveal that these waves can suffer breathing and broadening due to the diffraction effect. A remarkable split-off phenomenon of a spatial wave with wide stripes into several narrow and shallow oblique stripes is observed, as well as their passing and bouncing collisions.
Alatas, Husin [Theoretical Physics Division, Department of Physics, Bogor Agricultural University, Jl. Meranti, Kampus IPB Darmaga, Bogor 16680 (Indonesia)
Phase-wrapping artifacts, statistical image noise and the need for a minimum amount of phase steps per projection limit the practicability of x-ray grating based phase-contrast tomography, when using filtered back projection reconstruction. For conventional x-ray computed tomography, the use of statistical iterative reconstruction algorithms has successfully reduced artifacts and statistical issues. In this work, an iterative reconstruction method for grating based phase-contrast tomography is presented. The method avoids the intermediate retrieval of absorption, differential phase and dark field projections. It directly reconstructs tomographic cross sections from phase stepping projections by the use of a forward projecting imaging model and an appropriate likelihood function. The likelihood function is then maximized with an iterative algorithm. The presented method is tested with tomographic data obtained through a wave field simulation of grating based phase-contrast tomography. The reconstruction result...
Ritter, Andr�; Durst, J�rgen; G�del, Karl; Haas, Wilhelm; Michel, Thilo; Rieger, Jens; Weber, Thomas; Wucherer, Lukas; Anton, Gisela
Process Development for High Voc CdTe Solar Cells
This is a cumulative and final report for Phases I, II and III of this NREL funded project (subcontract # XXL-5-44205-10). The main research activities of this project focused on the open-circuit voltage of the CdTe thin film solar cells. Although, thin film CdTe continues to be one of the leading materials for large-scale cost-effective production of photovoltaics, the efficiency of the CdTe solar cells have been stagnant for the last few years. This report describes and summarizes the results for this 3-year research project.
Ferekides, C. S.; Morel, D. L.
Formation of ZnTe:Cu/Ti Contacts at High Temperature for CdS/CdTe Devices: Preprint
We study the performance of CdS/CdTe thin-film devices contacted with ZnTe:Cu/Ti of various thickness at a higher-than-optimum temperature of {approx}360 C. At this temperature, optimum device performance requires the same thickness of ZnTe:Cu as for similar contacts formed at a lower temperature of 320 C. C-V analysis indicates that a ZnTe:Cu layer thickness of {approx}< 0.5 mu m does not yield the degree of CdTe net acceptor concentration necessary to reduce space charge width to its optimum value for n-p device operation. The thickest ZnTe:Cu layer investigated (1 mu m) yields the highest CdTe net acceptor concentration, lowest value of Jo, and highest Voc. However, performance is limited for this device by poor fill factor. We suggest poor fill factor is due to Cu-related acceptors compensating donors in CdS.
Gessert, T. A.; Asher, S.; Johnston, S.; Duda, A.; Young, M. R.; Moriarty, T.
Science Conference Proceedings (OSTI)
The paper reports on the formation of the surface relief gratings in thin films of the azobenzene-functionalized polymer. We evidence that the efficiency of the formation process of the surface relief gratings strongly depends on the length of the main polymer chains in the case of the s-s configuration. The explanation of this relationship is given and is based on the revealing of the differences in the ability of the motion of the main chain which is strictly related to its length.
Sobolewska, Anna; Bartkiewicz, Stanislaw [Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)
Science Conference Proceedings (OSTI)
The paper reports on the formation of the surface relief gratings in thin films of the azobenzene-functionalized polymer. We evidence that the efficiency of the formation process of the surface relief gratings strongly depends on the length of the main polymer chains in the case of the s-s configuration. The explanation of this relationship is given and is based on the revealing of the differences in the ability of the motion of the main chain which is strictly related to its length.
Sobolewska, Anna; Bartkiewicz, Stanislaw [Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)
Modelling of a diode laser with a resonant grating of quantum wells and an external mirror
A three-dimensional numerical model of a diode laser with a resonant grating of quantum wells (QWs) and an external mirror is developed and used to calculate diode laser pulses that are long compared to the time of reaching a stationary regime and are short enough to neglect heating of the medium. The consistent solutions of the Helmholtz field equation and the system of diffusion equations for inversion in each QW are found. A source of charge carriers can be both an electron beam and a pump laser beam. The calculations yielded the longitudinal and radial profiles of the generated field, as well as its wavelength and power. The effective threshold pump current is determined. In the created iteration algorithm, the calculation time linearly increases with the number of QWs, which allows one to find the characteristics of lasers with a large number of QWs. The output powers and beam divergence angles of a cylindrical laser are calculated for different cavity lengths and pump spot radii. After calculating the fundamental mode characteristics, high-order modes were additionally calculated on the background of the frozen carrier distributions in the QW grating. It is shown that all the competing modes remain below the excitation threshold for the pump powers used in the experiment. The calculated and experimental data for the case of pumping by a nanosecond electron beam are qualitatively compared.
Vysotskii, D V; Elkin, N N; Napartovich, A P; Kozlovskii, Vladimir I; Lavrushin, B M
Noise in x-ray grating-based phase-contrast imaging
Science Conference Proceedings (OSTI)
Purpose: Grating-based x-ray phase-contrast imaging is a fast developing new modality not only for medical imaging, but as well for other fields such as material sciences. While these many possible applications arise, the knowledge of the noise behavior is essential. Methods: In this work, the authors used a least squares fitting algorithm to calculate the noise behavior of the three quantities absorption, differential phase, and dark-field image. Further, the calculated error formula of the differential phase image was verified by measurements. Therefore, a Talbot interferometer was setup, using a microfocus x-ray tube as source and a Timepix detector for photon counting. Additionally, simulations regarding this topic were performed. Results: It turned out that the variance of the reconstructed phase is only dependent of the total number of photons used to generate the phase image and the visibility of the experimental setup. These results could be evaluated in measurements as well as in simulations. Furthermore, the correlation between absorption and dark-field image was calculated. Conclusions: These results provide the understanding of the noise characteristics of grating-based phase-contrast imaging and will help to improve image quality.
Weber, Thomas; Bartl, Peter; Bayer, Florian; Durst, Juergen; Haas, Wilhelm; Michel, Thilo; Ritter, Andre; Anton, Gisela [ECAP--Erlangen Centre for Astroparticle Physics, University of Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Pattern Recognition Lab, University of Erlangen-Nuremberg, Martensstr. 3, 91058 Erlangen, Germany and ECAP--Erlangen Centre for Astroparticle Physics, University of Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); ECAP--Erlangen Centre for Astroparticle Physics, University of Erlangen-Nuremberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany)
Integrated municipal solid waste treatment using a grate furnace incinerator: The Indaver case
An integrated installation for treatment of municipal solid waste and comparable waste from industrial origin is described. It consists of three grate furnace lines with flue gas treatment by half-wet scrubbing followed by wet scrubbing, and an installation for wet treatment of bottom ash. It is demonstrated that this integrated installation combines high recovery of energy (40.8% net) with high materials recovery. The following fractions were obtained after wet treatment of the bottom ash: ferrous metals, non-ferrous metals, three granulate fractions with different particle sizes, and sludge. The ferrous and non-ferrous metal fractions can both be recycled as high quality raw materials; the two larger particle size particle fractions can be applied as secondary raw materials in building applications; the sand fraction can be used for applications on a landfill; and the sludge is landfilled. For all components of interest, emissions to air are below the limit values. The integrated grate furnace installation is characterised by zero wastewater discharge and high occupational safety. Moreover, with the considered installation, major pollutants, such as PCDD/PCDF, Hg and iodine-136 are to a large extent removed from the environment and concentrated in a small residual waste stream (flue gas cleaning residue), which can be landfilled after stabilisation.
Vandecasteele, C. [Department of Chemical Engineering, Katholieke Universiteit Leuven, De Croylaan 46, 3001 Leuven (Belgium)], E-mail: email@example.com; Wauters, G. [Indaver, Dijle 17a, 2800 Mechelen (Belgium); Arickx, S. [Department of Chemical Engineering, Katholieke Universiteit Leuven, De Croylaan 46, 3001 Leuven (Belgium); Jaspers, M. [Indaver, Dijle 17a, 2800 Mechelen (Belgium); Van Gerven, T. [Department of Chemical Engineering, Katholieke Universiteit Leuven, De Croylaan 46, 3001 Leuven (Belgium)
Supply Chain Dynamics of Tellurium (Te), Indium (In), and Gallium...
NLE Websites -- All DOE Office Websites (Extended Search)
CdTe Solar Cells, Solar Energy Materials and Solar Cells, 90 (2006) 2263-2271. 3 CRC Handbook of Chemistry and Physics, CRC Press, Boca Raton, FL, 1986. 4 M.A. Green, K....
VUV Detector Calibrations - CsTe Photodiode Description
Science Conference Proceedings (OSTI)
... telluride (CsTe) photodetectors with magnesium fluoride (MgF 2 ) windows are issued by ... telluride film is deposited onto a MgF 2 window and then ...
Synthesis and characterization of ZnTe hierarchical nanostructures
Science Conference Proceedings (OSTI)
Single-crystalline ZnTe hierarchical nanostructures have been successfully synthesized by a simple thermal evaporation technology. The as-prepared products were characterized with X-ray diffraction (XRD), scanning electron microcopy (SEM), transmission ...
Baohua Zhang; Fuqiang Guo; Wei Wang
Extreme solid state refrigeration using nanostructured Bi-Te alloys.
Materials are desperately needed for cryogenic solid state refrigeration. We have investigated nanostructured Bi-Te alloys for their potential use in Ettingshausen refrigeration to liquid nitrogen temperatures. These alloys form alternating layers of Bi{sub 2} and Bi{sub 2}Te{sub 3} blocks in equilibrium. The composition Bi{sub 4}Te{sub 3} was identified as having the greatest potential for having a high Ettingshausen figure of merit. Both single crystal and polycrystalline forms of this material were synthesized. After evaluating the Ettingshausen figure of merit for a large, high quality polycrystal, we simulated the limits of practical refrigeration in this material from 200 to 77 K using a simple device model. The band structure was also computed and compared to experiments. We discuss the crystal growth, transport physics, and practical refrigeration potential of Bi-Te alloys.
Lima Sharma, Ana L. (San Jose State University, San Jose, CA); Spataru, Dan Catalin; Medlin, Douglas L.; Sharma, Peter Anand; Morales, Alfredo Martin
This paper summarizes the following R&D accomplishments at National Renewable Energy Laboratory (NREL): (1) Developed several novel materials and world-record high-efficiency CdTe solar cell, (2) Developed "one heat-up step" manufacturing processes, and (3) Demonstrated 13.9% transparent CdTe cell and 15.3% CdTe/CIS polycrystalline tandem solar cell. Cadmium telluride has been well recognized as a promising photovoltaic material for thin-film solar cells because of its near-optimum bandgap of ~1.5 eV and its high absorption coefficient. Impressive results have been achieved in the past few years for polycrystalline CdTe thin-film solar cells at NREL. In this paper, we summarize some recent R&D activities at NREL.
Wu, X.; Zhou, J.; Keane, J. C.; Dhere, R. G.; Albin, D. S.; Gessert, T. A.; DeHart, C.; Duda, A.; Ward, J. J.; Yan, Y.; Teeter, G.; Levi, D. H.; Asher, S.; Perkins, C.; Moutinho, H. R.; To, B.
Strategies for recycling CdTe photovoltaic modules
Recycling end-of-life cadmium telluride (CdTe) photovoltaic (PV) modules may enhance the competitive advantage of CdTe PV in the marketplace, but the experiences of industries with comparable Environmental, Health and Safety (EH&S) challenges suggest that collection and recycling costs can impose significant economic burdens. Customer cooperation and pending changes to US Federal law may improve recycling economics.
Eberspacher, C.; Gay, C.F. [UNISUN, Newbury Park, CA. (United States); Moskowitz, P.D. [Brookhaven National Lab., Upton, NY (United States)
Phonon conduction in PbSe, PbTe, and PbTe1?xSex from first-principles calculations
We apply first-principles calculations to lead selenide (PbSe) and lead telluride (PbTe) and their alloys (PbTe[subscript 1?x]Se[subscript x]), which are potentially good thermoelectric materials, to investigate their ...
Tian, Zhiting
Science Conference Proceedings (OSTI)
We developed a simple and efficient method for synthesizing Te nanowires from CdTe nanoparticles with ethylenediaminetetraacetic acid disodium salt dehydrate (EDTA) as shape controller under hydrothermal condition. The systemcould both complete the transformation ...
Fangfang Xue; Ning Bi; Jiangong Liang; Heyou Han
Presented at the 2001 NCPV Program Review Meeting: Cathodoluminescence used to study evolution of electro-optical properties of back surface of CdS/CdTe during initial steps of fabricating NREL ZnTe:Cu contact.
Gessert, T. A.; Romero, M. J.; Asher, S. E.
Science Conference Proceedings (OSTI)
This paper presents ambient and high pressure measurements of transport properties of the Bi2Te3-Sb2Te3 series of materials. The electrical resistivity, thermal conductivity, and Seebeck coefficient have been measured on both end compounds and the direct solid solution of the two at pressure up to 10 GPa. An additional discussion involving the high pressure structure will be presented. From this, it was determined that these materials undergo at least two structural phase transitions between 0 and 20 GPa and a discussion is presented regarding this and the changes in the transport properties.
Jacobsen, M.K.; Sinogeikin, S.V.; Kumar, R.S.; Cornelius, A.L. (UNLV); (CIW)
Efficiency enhancement in a light-emitting diode with a two-dimensional surface grating photonic 21 November 2003 We demonstrate a light-emitting diode exhibiting 1.72.7-fold enhancement in light light emitting diode LED , the ef- ficiency is limited to several percents by a low light extrac- tion
Baba, Toshihiko
The Influence of Flue Gas Recirculation on the Formation of NOx in the Process of Coal Grate-Fired
Science Conference Proceedings (OSTI)
With the improvement of environmental protection requirements, the problems of NOx emission from industrial boiler become more and more notable. To explore a real effective method of low NOx combustion, the article discusses the influence of flue gas ... Keywords: flue gas recirculation, grate-fired, temperature, Nox
Li Xu; Jianmin Gao; Guangbo Zhao; Laifu Zhao; Zhifeng Zhao; Shaohua Wu
We study the performance of CdS/CdTe thin film PV devices processed with a ZnTe:Cu/Ti contact to investigate how carrier lifetime in the CdTe layer is affected by Cu diffusion from the contact.
Gessert, T. A.; Metzger, W. K.; Asher, S. E.; Young, M. R.; Johnston, S.; Dhere, R. G.; Duda, A.
A soft x-ray transmission grating imaging-spectrometer for the National Ignition Facility
A soft x-ray transmission grating spectrometer has been designed for use on high energy-density physics experiments at the National Ignition Facility (NIF); coupled to one of the NIF gated x-ray detectors (GXD) it records sixteen time-gated spectra between 250 and 1000eV with 100ps temporal resolution. The trade-off between spectral and spatial resolution leads to an optimized design for measurement of emission around the peak of a 100-300eV blackbody spectrum. Performance qualification results from the NIF, the Trident Laser Facility and VUV beamline at the National Synchrotron Light Source (NSLS), evidence a <100{micro}m spatial resolution in combination with a source-size limited spectral resolution that is <10eV at photon energies of 300eV.
Moore, A S; Guymer, T M; Kline, J L; Morton, J; Taccetti, M; Lanier, N E; Bentley, C; Workman, J; Peterson, B; Mussack, K; Cowan, J; Prasad, R; Richardson, M; Burns, S; Kalantar, D H; Benedetti, L R; Bell, P; Bradley, D; Hsing, W; Stevenson, M
Beam dynamics and wakefield simulations of the double grating accelerating structure
Science Conference Proceedings (OSTI)
Laser-driven acceleration in dielectric structures can provide gradients on the order of GeV/m. The small transverse dimension and tiny feature sizes introduce challenges in design, fabrication, and simulation studies of these structures. In this paper we present the results of beam dynamic simulation and short range longitudinal wakefield simulation of the double grating structure. We show the linear trend of acceleration in a dielectric accelerator design and calculate the maximum achievable gradient equal to 0.47E{sub 0} where E0 is maximum electric field of the laser excitation. On the other hand, using wakefield simulations, we show that the loss factor of the structure with 400nm gap size will be 0.12GV/m for a 10fC, 100as electron bunch which is an order of magnitude less than expected gradient near damage threshold of the device.
Najafabadi, B. Montazeri; Byer, R. L.; Ng, C. K.; England, R. J.; Peralta, E. A.; Soong, K.; Noble, R.; Wu, Z. [Stanford University, Stanford, CA (United States); SLAC National Accelerator Laboratory, Menlo Park, CA (United States)
A soft x-ray transmission grating imaging-spectrometer for the National Ignition Facility
A soft x-ray transmission grating spectrometer has been designed for use on high energy-density physics experiments at the National Ignition Facility (NIF); coupled to one of the NIF gated x-ray detectors it records 16 time-gated spectra between 250 and 1000 eV with 100 ps temporal resolution. The trade-off between spectral and spatial resolution leads to an optimized design for measurement of emission around the peak of a 100-300 eV blackbody spectrum. Performance qualification results from the NIF, the Trident Laser Facility and vacuum ultraviolet beamline at the National Synchrotron Light Source, evidence a <100 {mu}m spatial resolution in combination with a source-size limited spectral resolution that is <10 eV at photon energies of 300 eV.
Moore, A. S.; Guymer, T. M.; Morton, J.; Bentley, C.; Stevenson, M. [Directorate Science and Technology, AWE Aldermaston, Reading, RG7 4PR (United Kingdom); Kline, J. L.; Taccetti, M.; Lanier, N. E.; Workman, J.; Peterson, B.; Mussack, K.; Cowan, J. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Prasad, R.; Richardson, M.; Burns, S.; Kalantar, D. H.; Benedetti, L. R.; Bell, P.; Bradley, D.; Hsing, W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States)
We study the effects of Cu composition on the CdTe/ZnTe:Cu back contact and the bulk CdTe. For the back contact, its potential barrier decreases with Cu concentration while its saturation current density increases. For the bulk CdTe, the hole density increases with Cu concentration. We identify a Cu-related deep level at {approx}0.55 eV whose concentration is significant when the Cu concentration is high. The device performance, which initially increases with Cu concentration then decreases, reflects the interplay between the positive influences and negative influences (increasing deep levels in CdTe) of Cu.
Li, J. V.; Duenow, J. N.; Kuciauskas, D.; Kanevce, A.; Dhere, R. G.; Young, M. R.; Levi, D. H.
The half-life of {sup 131g,m}Te
In this work, the half-lives of {sup 131m}Te and {sup 131g}Te were measured. Radioactive sources of {sup 131}Te were obtained using the {sup 130}Te(n,{gamma}){sup 131}Te nuclear reaction. These nuclear parameters have been determined with a better confidence and accuracy than previously available: 18.89 {+-} 0.11 min and 33.18 {+-} 0.13 h, respectively. These results are quite helpful for new calculations that attempt to describe the low-lying levels in {sup 131}I from the decay of {sup 131g,m}Te.
Ruivo, J. C.; Zamboni, C. B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN / CNEN - SP) Av. Professor Lineu Prestes 2242 05508-000 Sao Paulo, SP (Brazil); Oliveira, J. R. B. [Instituto de Fisica da Universidade de Sao Paulo, Brazil Travessa R da Rua do Matao 187 05508-090 Sao Paulo, SP (Brazil); Heder Medina, Nilberto
A 3 TeV Muon Collider Lattice Design
A new lattice for 3 TeV c.o.m. energy with {beta}* = 5mm was developed which follows the basic concept of the earlier 1.5 TeV design but uses quad triplets for the final focus in order to keep the maximum magnet strength and aperture close to those in 1.5 TeV case. Another difference is employment of combined-function magnets with the goal to lower heat deposition in magnet cold mass and to eliminate bending field free regions which produce 'hot spots' of neutrino radiation that can be an issue at higher energy. The proposed lattice is shown to satisfy the requirements on luminosity, dynamic aperture and momentum acceptance.
Alexahin, Y.; Gianfelice-Wendt, E.; /Fermilab
CdTe and Cd0.9Zn0.1Te Crystal Growth and Characterization for Nuclear Spectrometers
Science Conference Proceedings (OSTI)
Large volume single crystals of CdTe and Cd0.9Zn0.1Te (CZT) have been grown by a controlled vertical Bridgman technique using in-house zone refined precursors and characterized through structural, electrical, optical, and spectroscopic methods. The grown crystals (diameter greater than or equal to 2.5 cm and length >10 cm) have shown promising characteristics for high-resolution room temperature solid-state radiation detectors due to their high resistivity (~1010 -cm for CdTe, and >1011 -cm for CZT) and good charge transport properties [ e ~ (2-5)x10-3 cm2/V]. The fabricated detectors in planar single element and Frisch collar configurations have shown very low leakage currents and high count rates for various sources, including Am-241, and Cs-137. The grown crystals have been further characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), and transmission two-modulator generalized ellipsometry (2-MGE). Details of the CdTe and CZT characterization results, detector fabrication steps, and testing with radiation sources are presented. The CdTe and CZT crystals have shown high prospects for low power rating solid-state nuclear spectrometers and medical imaging devices.
Mandal, Krishna [EIC Laboratories, Inc.; Kang, Sung Hoon [EIC Laboratories, Inc.; Choi, Michael [EIC Laboratories, Inc.; Wright, Gomez W [ORNL; Jellison Jr, Gerald Earle [ORNL
High contrast, CdTe portal scanner for radiation therapy
Science Conference Proceedings (OSTI)
This paper reports on one of the most promising new technologies for improving the qualify of radiation therapy, the use of real-time systems to produce portal images. In the authors' approach, they are constructing a linear array of 256 CdTe photovoltaic detectors attached to a very compact linear scanner, all of which will be mounted in a cassette shaped package to be located under the patient table. The high stopping power of the CdTe allows a high contrast image to be made using only a single Linac pulse per line, resulting in a high contrast image in under 5 seconds.
Entine, G.; Squillante, M.R.; Hahn, R.; Cirignano, L.J.; McGann, W. (Radiation Monitoring Devices, Inc., Watertown, MA (United States)); Biggs, P.J. (Massachusetts General Hospital, Boston, MA (United States))
Formation of ZnTe:Cu/Ti Contacts at High Temperature for CdS/CdTe Devices (Presentation)
The conclusions of this report are that Cu diffusion from a ZnTe:Cu contact causes good and bad things. The good (Cu in CdS < low 10{sup 18} cm{sup -3})--increase in CdTe N{sub A}-N{sub D} that leads to V{sub oc} and FF improvement. The bad (Cu in CdS > low 10{sup 18} cm{sup -3})--(1) possibly decreased of shunt resistance (?); (2) depletion width in CdTe can become too narrow for optimum current collection at J{sub MPP}; (3) donor reduction in CdS (significant FF loss in LIV); and (4) excessive Cu diffusion into CdS readily observed by red-light bias QE.
Gessert, T. A.; Asher, S.; Johnston, S.; Duda, A.; Young, M. R.; Moriarty, T.
Electrophysical properties of semimagnetic solid solutions Hg 1?x Mn x Te
Science Conference Proceedings (OSTI)
A comprehensive study of the electrophysical properties of the semimagnetic ternary solid solution Hg 1?x Mn x Te an alternative material to Hg 1?x Cd x Te is reported. The charge-carrier scattering
I. M. Nesmelova; V. N. Ryzhkov; M. I. Ibragimova; V. Yu. PetukhovKazan Physicotechnical Institute, Kazan Research Center of the Russian Academy of Sciences, Kazan?420029, Russia
Micro-PL Studies of Polycrustalline CdS/CdTe Interfaces
We describe a technique of photoluminescence measurements with a resolutiion of microns. This technique is applied to examine the CdS/CdTe interface of CdTe solar cells.
Dhere, R.; Cheong, M.; Smith, S.; Albin, D.; Mascarenhas, A.; Gessert, T. A.
V-183: Cisco TelePresence TC and TE Bugs Let Remote Users Deny...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
3: Cisco TelePresence TC and TE Bugs Let Remote Users Deny Service and Remote Adjacent Authenticated Users Gain Root Shell Access V-183: Cisco TelePresence TC and TE Bugs Let...
Feasibility of GRB with TeV gamma ray all sky monitor
We discuss feasibility of Gamma ray burst (GRB) with TeV gamma ray all sky monitor and discuss necessity of TeV gamma ray cherenkov all sky monitor.
S. Osone
Junction Evolution During Fabrication of CdS/CdTe Thin-film PV Solar Cells (Presentation)
Discussion of the formation of CdTe thin-film PV junctions and optimization of CdTe thin-film PV solar cells.
Gessert, T. A.
Detector Performance of Ammonium-Sulfide-Passivated CdZnTe and CdMnTe Materials
Science Conference Proceedings (OSTI)
Dark currents, including those in the surface and bulk, are the leading source of electronic noise in X-ray and gamma detectors, and are responsible for degrading a detector's energy resolution. The detector material itself determines the bulk leakage current; however, the surface leakage current is controllable by depositing appropriate passivation layers. In previous research, we demonstrated the effectiveness of surface passivation in CZT (CdZnTe) and CMT (CdMnTe) materials using ammonium sulfide and ammonium fluoride. In this research, we measured the effect of such passivation on the surface states of these materials, and on the performances of detectors made from them.
Kim, K.H.; Bolotnikov, A.E.; Camarda, G.S.; Marchini, L.; Yang, G.; Hossain, A.; Cui, Y.; Xu, L.; and James, R.B.
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
DioxiDe CaPture teChnology sheets national energy teChnology laboratory aDvanCeD aCiD gas seParation teChnology for the utilization of low-rank Coals primary project goals Air...
School of Mathematical and Computing Sciences Te Kura Pangarau, Rorohiko
#12;School of Mathematical and Computing Sciences Te Kura Pangarau, Rorohiko Vortex geometry constant throughout the fluid flow. The velocity of the fluid flow is v = (A ^r + B ^) r . Use constant throughout the fluid flow. The velocity of the fluid flow is v = (A ^r + B ^) r . Streamlines are equiangular
Visser, Matt
Diffuse TeV Emission at the Galactic Centre
The High-Energy Stereoscopic System (HESS) has detected intense diffuse TeV emission correlated with the distribution of molecular gas along the galactic ridge at the centre of our Galaxy. Earlier HESS observations of this region had already revealed the presence of several point sources at these energies, one of them (HESS J1745-290) coincident with the supermassive black hole Sagittarius A*. It is still not entirely clear what the origin of the TeV emission is, nor even whether it is due to hadronic or leptonic interactions. It is reasonable to suppose, however, that at least for the diffuse emission, the tight correlation of the intensity distribution with the molecular gas indicates a pionic-decay process involving relativistic protons. In this paper, we explore the possible source(s) of energetic hadrons at the galactic centre, and their propagation through a turbulent medium. We conclude that though Sagittarius A* itself may be the source of cosmic rays producing the emission in HESS J1745-290, it cannot be responsible for the diffuse emission farther out. A distribution of point sources, such as pulsar wind nebulae dispersed along the galactic plane, similarly do not produce a TeV emission profile consistent with the HESS map. We conclude that only a relativistic proton distribution accelerated throughout the inter-cloud medium can account for the TeV emission profile measured with HESS.
Elizabeth Wommer; Fulvio Melia; Marco Fatuzzo
TeV Dark Matter detection by Atmospheric Cerenkov Telescopes
Ground based Atmospheric Cerenkov Telescopes have recently unveiled a TeV gamma-ray signal from the direction of the Galactic Centre. We examine whether these gamma-rays, observed by the VERITAS, CANGAROO-II and HESS collaborations, may arise from annihilations of dark matter particles. Emission from nearby dwarf spheroidals, such as Sagittarius, could provide a test of this scenario.
Francesc Ferrer
The BL Lac object H1426+428 was recently detected as a high energy gamma-ray source by the VERITAS collaboration (Horan et al. 2002). We have reanalyzed the 2001 portion of the data used in the detection in order to examine the spectrum of H1426+428 above 250 GeV. We find that the time-averaged spectrum agrees with a power law of the shape dF/dE = 10^(-7.31 +- 0.15(stat) +- 0.16(syst)) x E^(-3.50 +- 0.35(stat) +- 0.05(syst)) m^(-2)s^(-1)TeV^(-1) The statistical evidence from our data for emission above 2.5 TeV is 2.6 sigma. With 95% c.l., the integral flux of H1426+428 above 2.5 TeV is larger than 3% of the corresponding flux from the Crab Nebula. The spectrum is consistent with the (non-contemporaneous) measurement by Aharonian et al. (2002) both in shape and in normalization. Below 800 GeV, the data clearly favours a spectrum steeper than that of any other TeV Blazar observed so far indicating a difference in the processes involved either at the source or in the intervening space.
D. Petry; I. H. Bond; S. M. Bradbury; J. H. Buckley; D. A. Carter-Lewis; W. Cui; C. Duke; I. de la Calle Perez; A. Falcone; D. J. Fegan; S. J. Fegan; J. P. Finley; J. A. Gaidos; K. Gibbs; S. Gammell; J. Hall; T. A. Hall; A. M. Hillas; J. Holder; D. Horan; M. Jordan; M. Kertzman; D. Kieda; J. Kildea; J. Knapp; K. Kosack; F. Krennrich; S. LeBohec; P. Moriarty; D. M�ller; T. N. Nagai; R. Ong; M. Page; R. Pallassini; B. Power-Mooney; J. Quinn; N. W. Reay; P. T. Reynolds; H. J. Rose; M. Schroedter; G. H. Sembroski; R. Sidwell; N. Stanton; S. P. Swordy; V. V. Vassiliev; S. P. Wakely; G. Walker; T. C. Weekes
Carrier dynamics and activation energy of CdTe quantum dots in a Cd{sub x}Zn{sub 1-x}Te quantum well
We investigate the optical properties of CdTe quantum dots (QDs) in a Cd{sub 0.3}Zn{sub 0.7}Te quantum well (QW) grown on GaAs (100) substrates. Carrier dynamics of CdTe/ZnTe QDs and quantum dots-in-a-well (DWELL) structure is studied using time-resolved photoluminescence (PL) measurements, which show the longer exciton lifetime of the DWELL structure. The activation energy of the electrons confined in the DWELL structure, as obtained from the temperature-dependent PL spectra, was also higher than that of electrons confined in the CdTe/ZnTe QDs. This behavior is attributed to the better capture of carriers into QDs within the surrounding QW.
Han, W. I.; Lee, J. H.; Yu, J. S.; Choi, J. C. [Department of Physics, Yonsei University, Wonju 220-710 (Korea, Republic of); Lee, H. S. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)
Diffraction at a time grating in above-threshold ionization: The influence of the Coulomb potential
We analyze the photoelectron emission spectrum in atomic above-threshold ionization by a linearly polarized short-laser pulse. Direct electrons can be characterized by both intracycle and intercycle interferences. The former results from the coherent superposition of two different electron trajectories released in the same optical cycle, whereas the latter is the consequence of the superposition of multiple trajectories released in different cycles. In the present article, a semiclassical analytical expression for the complete (both intracycle and intercycle) interference pattern is derived. We show that the recently proposed semiclassical description in terms of a diffraction process at a time grating remains qualitatively unchanged in the presence of the long-range Coulomb potential. The latter causes only a phase shift of the intracycle interference pattern. We verify the predictions of the semiclassical model by comparison with full three-dimensional (3D) time-dependent Schroedinger equation (TDSE) solutions. One key finding is that the subcycle interference structures originating from trajectories launched within a time interval of less than 1 femtosecond should be experimentally observable also in low-resolution spectra for longer multicycle pulses.
Arbo, Diego G. [Institute for Astronomy and Space Physics, IAFE (CONICET-UBA), CC 67, Suc. 28 (1428) Buenos Aires (Argentina); Department of Physics, FCEN, University of Buenos Aires (Argentina); Ishikawa, Kenichi L. [Photon Science Center, Graduate School of Engineering, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656 (Japan); Schiessl, Klaus; Persson, Emil; Burgdoerfer, Joachim [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10/136, A-1040 Vienna (Austria)
Comparison of CdTe and CdZnTe Detectors for Field Determination of Uranium Isotopic Enrichments
A performance comparison of a CdTe and a CdZnTe detector when exposed to uranium samples of various isotopic enrichments has been performed. These high-resolution detectors can assist in the rapid determination of uranium isotopic content of illicit material. Spectra were recorded from these room temperature semiconductor detectors with a portable multi-channel analyzer, both in the laboratory and in a field environment. Both detectors were operated below ambient temperature using the vendor supplied thermoelectric coolers. Both detectors had nominally the same active volume (18 mm3 for the CdZnTe and 25 mm3 for the CdTe detector) and resolution. Spectra of samples of known isotopic content were recorded at fixed geometries. An evaluation of potential signature g rays for the detection of enriched uranium was completed. Operational advantages and disadvantages of each detector are discussed. There is a need to improve the detection sensitivity during the interdiction of special nuclear materials (SNM) for increased homeland protection. It is essential to provide additional tools to first responders and law enforcement personnel for assessing nuclear and radiological threats.
Hofstetter, KJ
Novel ways of depositing ZnTe films by a solution growth technique
An electrochemical process has been successfully developed for the reproducible deposition of ZnTe and copper-doped ZnTe films suitable as transparent ohmic contacts for CdS/CdTe solar cells. The development of this method and optimization of key processing steps in the fabrication of CdS/CdTe/ZnTe:Cu devices has allowed IEC to achieve cell performance results of FF>70% and {eta} {approximately}10%. Preliminary efforts have indicated that the deposition methods investigated are potentially feasible for the formation of other II-VI compounds for use in polycrystalline thin film solar devices and should be the focus of future work.
Birkmire, R.W.; McCandless, B.E.; Yokimcus, T.A.; Mondal, A. (Delaware Univ., Newark, DE (United States). Inst. of Energy Conversion)
A Note on TeV Cerenkov Events as Bose-Einstein Gamma Condensations
The idea that the TeV air showers, thought to be produced by >10 TeV gamma rays from Mrk 501, can be mimicked by coherent bunches of sub-TeV photons is reexamined, focusing on fundamental considerations. In particular, it is shown that the minimum spot size of the beam of pulsed TeV photons arriving at Earth is on the order of a few kilometers, unless a lens with certain characteristics is placed between the TeV laser and Earth. The viability of the laser production mechanism proposed by Harwit et al. (2000) is also reassessed.
Amir Levinson
This collection of proceedings to the TeV PA II Conference presents some of the latest results of the IceCube Collaboration.
IceCube Collaboration; A. Achterberg
Science Conference Proceedings (OSTI)
Keywords: HgCdTe, diffusion length, field effect transistor, hydrogenation, lifetime, mobility, photodiode
Han Jung; Hee Chul Lee; Choong-Ki Kim
Charge transport properties of CdMnTe radiation detectors
Science Conference Proceedings (OSTI)
Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe)radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading chargecollection is reduced with increasing values of bias voltage. The electron transit time was determined from time of flight measurements. From the dependence of drift velocity on applied electric field the electron mobility was found to be n = (718 55) cm2/Vs at room temperature.
Kim K.; Rafiel, R.; Boardman, M.; Reinhard, I.; Sarbutt, A.; Watt, G.; Watt, C.; Uxa, S.; Prokopovich, D.A.; Belas, E.; Bolotnikov, A.E.; James, R.B.
Sub-barrier fusion enhancement with radioactive 134Te
The fusion cross sections of radioactive $^{134}$Te + $^{40}$Ca were measured at energies above and below the Coulomb barrier. The evaporation residues produced in the reaction were detected in a zero-degree ionization chamber providing high efficiency for inverse kinematics. Both coupled-channel calculations and comparison with similar Sn+Ca systems indicate an increased sub-barrier fusion probability that is correlated with the presence of positive Q-value neutron transfer channels. In comparison, the measured fusion excitation functions of $^{130}$Te + $^{58,64}$Ni, which have positive Q-value neutron transfer channels, were accurately reproduced by coupled-channel calculations including only inelastic excitations. The results demonstrate that the coupling of transfer channels can lead to enhanced sub-barrier fusion but this is not directly correlated with positive Q-value neutron transfer channels in all cases.
Z. Kohley; J. F. Liang; D. Shapira; C. J. Gross; R. L. Varner; J. M. Allmond; J. J. Kolata; P. E. Mueller; A. Roberts
TeV scale dark matter and electroweak radiative corrections
Recent anomalies in cosmic rays data, namely, from the PAMELA Collaboration, can be interpreted in terms of TeV scale decaying/annihilating dark matter. We analyze the impact of radiative corrections coming from the electroweak sector of the standard model on the spectrum of the final products at the interaction point. As an example, we consider virtual one loop corrections and real gauge bosons emission in the case of a very heavy vector boson annihilating into fermions. We find electroweak corrections that are relevant, but not as big as sometimes found in the literature; we relate this mismatch to the issue of gauge invariance. At scales much higher than the symmetry breaking scale, one loop electroweak effects are so big that eventually higher orders/resummations have to be considered: we advocate for the inclusion of these effects in parton shower Monte Carlo models aiming at the description of TeV scale physics.
Ciafaloni, Paolo; Urbano, Alfredo [INFN - Sezione di Lecce and Universita del Salento, Via per Arnesano, I-73100 Lecce (Italy)
High-efficiency large-area CdTe panels
The objective of this three year effort has been to develop an improved materials technology and fabrication process for limited volume production of 1 ft{sup 2} and 4 ft{sup 2} CdS/CdTe photovoltaic modules. The module stability objective by the end of this three year subcontract was to develop techniques to provide ten year life exploration with no greater than 10% degradation. In order to achieve these efficiency and stability objectives, the research program has been separated into tasks including: (1) analysis and characterization of CdS/CdTe Devices; (2) performance optimization on small cells; (3) encapsulation and stability testing; and (4) module efficiency optimization. 27 refs., 18 figs., 3 tabs.
Albright, S.P.; Chamberlin, R.R.; Jordan, J.F. (Photon Energy, Inc., El Paso, TX (USA))
Sub-barrier fusion enhancement with radioactive 134Te
Science Conference Proceedings (OSTI)
The fusion cross sections of radioactive 134Te + 40Ca were measured at energies above and below the Coulomb barrier. The evaporation residues produced in the reaction were detected in a zero-degree ionization chamber providing high efficiency for inverse kinematics. Both coupled-channel calculations and comparison with similar Sn + Ca systems indicate an increased sub-barrier fusion probability that is correlated with the presence of positive Q-value neutron transfer channels. In comparison, the measured fusion excitation functions of 130Te + 58,64Ni, which have positive Q-value neutron transfer channels, were accurately reproduced by coupled-channel calculations including only inelastic excitations. The results demonstrate that the coupling of transfer channels can lead to enhanced sub-barrier fusion but this is not directly correlated with positive Q-value neutron transfer channels in all cases.
Kohley, Zachary W [ORNL; Liang, J Felix [ORNL; Shapira, Dan [ORNL; Gross, Carl J [ORNL; Varner Jr, Robert L [ORNL; Allmond, James M [ORNL; Kolata, Jim J [University of Notre Dame, IN; Mueller, Paul Edward [ORNL; Roberts, Amy [University of Notre Dame, IN
MHK Projects/TE4 | Open Energy Information
TE4 TE4 < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":5,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"500px","height":"350px","centre":false,"title":"","label":"","icon":"File:Aquamarine-marker.png","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":52.3247,"lon":1.68765,"alt":0,"address":"","icon":"http:\/\/prod-http-80-800498448.us-east-1.elb.amazonaws.com\/w\/images\/7\/74\/Aquamarine-marker.png","group":"","inlineLabel":"","visitedicon":""}]}
Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering
Deposition of multilayers on saw-tooth substrates is a key step in the fabrication of multilayer blazed gratings (MBG) for extreme ultraviolet and soft x-rays. Growth of the multilayers can be perturbed by shadowing effects caused by the highly corrugated surface of the substrates, which results in distortion of the multilayer stack structure and degradation of performance of MBGs. To minimize the shadowing effects we used an ionbeam sputtering machine with a highly collimated atomic flux to deposit Mo/Si multilayers on saw-tooth substrates. The sputtering conditions were optimized by finding a balance between smoothening and roughening processes in order to minimize degradation of the groove profile in the course of deposition and at the same time to keep the interfaces of a multilayer stack smooth enough for high efficiency. An optimal value of energy of 200 eV for sputtering Kr{sup +} ions was found by deposition of test multilayers on flat substrates at a range of ion energies. Two saw-tooth substrates were deposited at energies of 200 eV and 700 eV for the sputtering ions. It was found that reduction of the ion energy improved the blazing performance of the MBG and resulted in a 40% gain in the diffraction efficiency due to better replication of the groove profile by the multilayer. As a result of the optimization performed, an absolute diffraction efficiency of 28.8% was achieved for the 2nd blaze order of the MBG with a groove density of 7350 lines/mm at a wavelength of 13.5 nm. Details of the growth behavior of the multilayers on flat and saw-tooth substrates are discussed in terms of the Linear Continuous Model of film growth.
Gawlitza, Peter; Cambie, Rossana; Dhuey, Scott; Gullikson, Eric; Warwick, Tony; Braun, Stefan; Yashchuk, Valeriy; Padmore, Howard
Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering
Deposition of multilayers on saw-tooth substrates is a key step in the fabrication of multilayer blazed gratings (MBG) for extreme ultraviolet and soft x-rays. Growth of the multilayers can be perturbed by shadowing effects caused by the highly corrugated surface of the substrates, which results in distortion of the multilayer stack structure and degradation of performance of MBGs. To minimize the shadowing effects, we used an ion-beam sputtering machine with a highly collimated atomic flux to deposit Mo/Si multilayers on saw-tooth substrates. The sputtering conditions were optimized by finding a balance between smoothening and roughening processes in order to minimize degradation of the groove profile in the course of deposition and at the same time to keep the interfaces of a multilayer stack smooth enough for high efficiency. An optimal value of energy of 200 eV for sputtering Kr{sup +} ions was found by deposition of test multilayers on flat substrates at a range of ion energies. Two saw-tooth substrates were deposited at energies of 200 eV and 700 eV for the sputtering ions. It was found that reduction of the ion energy improved the blazing performance of the MBG and resulted in a 40% gain in the diffraction efficiency due to better replication of the groove profile by the multilayer. As a result of the optimization performed, an absolute diffraction efficiency of 28.8% was achieved for the 2nd blaze order of the MBG with a groove density of 7350 lines/mm at a wavelength of 13.5 nm. Details of the growth behavior of the multilayers on flat and saw-tooth substrates are discussed in terms of the linear continuous model of film growth.
Voronov, D. L.; Cambie, R.; Dhuey, S.; Gullikson, E. M.; Warwick, T.; Yashchuk, V. V.; Padmore, H. A. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Gawlitza, P.; Braun, S. [Fraunhofer Institute for Material and Beam Technology, Winterbergstrasse 28, 01277 Dresden (Germany)
Variable Spaced Grating (VSG) Snout, Rotator and Rails for use at LLE
Science Conference Proceedings (OSTI)
The Variable Spaced Grating (VSG) is a spectrometer snout mounted to an X-Ray Framing Camera (XRFC) through the Unimount flange. This equipment already exists and is used at the University of Rochester, Laboratory for Laser Energetics (LLE) facility. The XRFC and the Unimount flange are designed by LLE. The Tilt Rotator fixture that mounts next to the XRFC and the cart rails are designed by LLNL, and are included in this safety note. The other related components, such as the TIM rails and the Unimount flange, are addressed in a separate safety note, EDSN09-500005-AA. The Multipurpose Spectrometer (MSPEC) and VSG are mounted on the TIM Boat through the cart rails that are very similar in design. The tilt rotator combination with the Unimount flange is also a standard mounting procedure. The later mounting system has been included in this safety note. Figure-1 shows the interface components and the VSG snout. Figure-2 shows the VSG assembly mounted on the Unimount flange. The calibration pointer attachment is shown in place of the snout. There are two types of VSG, one made of 6061-T6 aluminum, weighing approximately 3 pounds, and the other made of 304 stainless steel, weighing approximately 5.5 pounds. This safety note examines the VSG steel design. Specific experiments may require orienting the VSG snout in 90 degrees increment with respect to the Unimount flange. This is done by changing the bolts position on the VSG-main body adapter flange to the Unimount adapter plate. There is no hazard involved in handling the VSG during this procedure as it is done outside the target chamber on the cart rail before installing on the TIM. This safety note addresses the mechanical integrity of the VSG structure, the tilt rotating fixture, the cart rails with handle and their connections. Safety Factors are also calculated for the MSPEC in place of the VSG.
Mukherjee, S K; Emig, J A; Griffith, L V; Heeter, R F; House, F A; James, D L; Schneider, M B; Sorce, C M
Flat beams in a 50 TeV hadron collider
The basic beam dynamics of a next generation 50 x 50 TeV hadron collider based on a high field magnet approach have been outlined over the past several years. Radiation damping not only produces small emittances, but also flat beams, just as in electron machines. Based on {open_quotes}Snowmass 96{close_quotes} parameters, we investigate the issues associated with flat beams in very high energy hadron colliders.
Peggs, S.; Harrison, M.; Pilat, F.; Syphers, M.
Mr. John E. Kieling, Chief Hazardous Was te Bureau
NLE Websites -- All DOE Office Websites (Extended Search)
John E. Kieling, Chief John E. Kieling, Chief Hazardous Was te Bureau Depa rtment of Energy Carlsbad Field Office P. O. Box 3090 Carlsbad , New Mexico 88221 NOV 0 5 2013 New Mexico Environment Department 2905 Rodeo Park Drive East. Building 1 Santa Fe, New Mexico 87505-6303 Subject: Panel 6 Closure and Final Waste Emplacement Notifications Dear Mr. Kieling : The purpose of this leiter is 1 0 notify th e New Mexico Environment Department (NMEO) that the
ELUTIONS Inc formerly TeCom | Open Energy Information
ELUTIONS Inc formerly TeCom ELUTIONS Inc formerly TeCom Jump to: navigation, search Name ELUTIONS Inc (formerly TeCom) Place Tampa, Florida Zip 33605 Sector Efficiency Product Tampa-based wireless enterprise automation solutions firm. Elutions provides an Active Energy Management service allowing users to increase efficiency by monitoring, forecasting and analyzing utility resource consumption. Coordinates 27.94653°, -82.459269° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":27.94653,"lon":-82.459269,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
This conference paper describes the alloying between CdS and CdTe at the CdS/CdTe interface is a function of the growth temperature and post-deposition CdCl2 heat treatment (HT). In devices prepared by different techniques, Te-rich CdSxTe1-x alloys with x= 0.04 to 0.08 have been identified. We present our work on thin-film couples of CdS and CdTe, which can withstand higher level of CdCl2 treatment without the adhesion problems typically encountered in the regular device structure. CdS films with a thickness of {approx}100 nm were deposited by chemical-bath deposition on glass/SnO2 substrates, and CdTe films with a thickness of 300 and 800 nm were deposited by close-spaced sublimation. The samples were treated in the presence of vapor CdCl2 at 400-450 C for 5 min. X-ray diffraction and optical analysis of the samples showed that S content in the CdSxTe1-x alloy increased systematically with the CdCl2 HT temperature. CdSxTe1-x alloy with x= 0.14 was identified for the samples treated at 4 30C, which is much higher than expected from the miscibility gap at 430C.
Dhere, R.; Wu, X.; Albin, D.; Perkins, C.; Moutinho, H.; Gessert, T.
The main focus of the work at NREL was on the development of Cu-doped ZnTe contacts to CdTe solar cells in the substrate configuration. The work performed under the CRADA utilized the substrate device structure used at NREL previously. All fabrication was performed at NREL. We worked on the development of Cu-doped ZnTe as well as variety of other contacts such as Sb-doped ZnTe, CuxTe, and MoSe2. We were able to optimize the contacts to improve device parameters. The improvement was obtained primarily through increasing the open-circuit voltage, to values as high as 760 mV, leading to device efficiencies of 7%.
Dhere, R.
Spectral Filtering in a Diode-Pumped Nd:YLF Regenerative Amplifier Using a Volume Bragg Grating
Science Conference Proceedings (OSTI)
Instrument-limited suppression of out-of-band Amplified Spontaneous Emission (ASE) is demonstrated in a Nd:YLF Diode-Pumped Regenerative Amplifier (DPRA) using a Volume Bragg Grating (VBG) as a spectrally selective reflective element. A VBG with 99.4% diffraction efficiency and 230-pm-FWHM reflection bandwidth produced a 43-pm-FWHM output spectral width in an unseeded DPRA compared to 150-pm FWHM in the same DPRA with no VBG. Instrument-limited ASE suppression is even observed when the DPRA seed pulse energy approaches the ASE background.
Okishev, A.V.; Dorrer, C.; Smirnov, V.I.; Glebov, L.B.; Zuegel, J.D.
We report on the application of a two-dimensional hard x-ray grating interferometer to x-ray optics metrology. The interferometer is sensitive to refraction angles in two perpendicular directions with a precision of 10 nrad. It is used to observe the wavefront changes induced by a single parabolic beryllium focusing lens of large radius of curvature. The lens shape is reconstructed and its residual aberrations are analyzed. Its profile differs from an ideal parabolic shape by less than 2 {mu}m or {lambda}/50 at {lambda} = 0.54 A wavelength.
Rutishauser, Simon; David, Christian [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Zanette, Irene [European Synchrotron Radiation Facility, 38043 Grenoble (France); Weitkamp, Timm [Synchrotron Soleil, 91192 Gif-sur-Yvette (France); Donath, Tilman [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Dectris Ltd., 5400 Baden (Switzerland)
Bismuth-induced deep levels and carrier compensation in CdTe
Science Conference Proceedings (OSTI)
First-principles calculations show that Bi on Cd site in CdTe can be either a donor, Bi_Cd+, or an acceptor, Bi_Cd- , depending on the Fermi level. The can bind a substitutional O (O_Te) with large binding energy of 1.40 eV. The calculated (0/-) transition level for B_Cd- - O_Te complex is in good agreement with the observed deep hole trapping level. Bi can also substitute Te to form an acceptor. The amphoteric nature of Bi in CdTe results in the pinning of the Fermi level and the high resistivity. We also discuss the origin of p-type CdTe at high Bi doping level.
Du, Mao-Hua [ORNL
The Effect of Structural Vacancies on the Thermoelectric Properties of (Cu2Te)1-x(Ga2Te3)x
We have studied the effects of structural vacancies on the thermoelectric properties of the ternary compounds (Cu2Te)1-x(Ga2Te3)x (x = 0.5, 0.55, 0.571, 0.6, 0.625, 0.667 and 0.75), which are solid solutions found in the pseudo-binary phase diagram for Cu2Te and Ga2Te3. This system possesses tunable structural vacancy concentrations. The x= 0.5 phase, CuGaTe2, is nominally devoid of structural vacancies, while the rest of the compounds contain varying amounts of these features, and the volume density of vacancies increases with Ga2Te3 content. The sample with x = 0.5, 0.55, 0.571, 0.6, 0.625 crystallize in the chalcopyrite structure while the x = 0.667 and 0.75 adopt the Ga2Te3 defect zinc blende structure. Strong scattering of heat carrying phonons by structural defects, leads to the reduction of thermal conductivity, which is beneficial to the thermoelectric performance of materials. On the other hand, these defects also scatter charge carriers and reduce the electrical conductivity. All the samples investigated are p-type semiconductors as inferred by the signs of their respective Hall (RH) and Seebeck (S) coefficients. The structural vacancies were found to scatter phonons strongly, while a combination of increased carrier concentration, and vacancies decreases the Hall mobility ( H), degrading the overall thermoelectric performance. The room temperature H drops from 90 cm2/V s for CuGaTe2 to 13 cm2/V s in Cu9Ga11Te21 and 4.6 cm2/V s in CuGa3Te5. The low temperature thermal conductivity decreases significantly with higher Ga2Te3 concentrations (higher vacancy concentration) due to increased point defect scattering which dominate thermal resistance terms. At high temperatures, the dependence of thermal conductivity on the Ga2Te3 content is less significant. The presence of strong Umklapp scattering leads to low thermal conductivity at high temperatures for all samples investigated. The highest ZT among the samples in this study was found for the defect-free CuGaTe2 with ZT ~ 1.0 at 840K.
Ye, Zuxin [GM Research and Development Center; Cho, Jung Y [GM R& D and Planning, Warren, Michigan; Tessema, Misle [GM Research and Development Center; Salvador, James R. [GM R& D and Planning, Warren, Michigan; Waldo, Richard [GM R& D and Planning, Warren, Michigan; Wang, Hsin [ORNL; Cai, Wei [ORNL
Novel CdTe Cell Fabrication Process with Potential for Low Cost and High Throughput
There are several production disadvantages inherent in the conventional SnO(2)/CdS/CdTe manufacturing processes. In this paper, we report a novel manufacturing process for fabrication of polycrystalline Cd(2)SnO(4)/Zn(2)/SnO(4)/CdS/CdTe thin-film solar cells that yielded a CdS/CdTe device with an NREL-confirmed efficiency of 14.0%.
Wu, X.; Sheldon, P.
High Efficiency Single Crystal CdTe Solar Cells: November 19, 2009 - January 31, 2011
The goal of the program was to develop single crystal CdTe-based top cells grown on Si solar cells as a platform for the subsequent manufacture of high efficiency tandem cells for CPV applications. The keys to both the single junction and the tandem junction cell architectures are the ability to grow high quality single-crystal CdTe and CdZnTe layers on p-type Si substrates, to dope the CdTe and CdZnTe controllably, both n and p-type, and to make low resistance ohmic front and back contacts. EPIR demonstrated the consistent MBE growth of CdTe/Si and CdZnTe/Si having high crystalline quality despite very large lattice mismatches; epitaxial CdTe/Si and CdZnTe/Si consistently showed state-of-the-art electron mobilities and good hole mobilities; bulk minority carrier recombination lifetimes of unintentionally p-doped CdTe and CdZnTe grown by MBE on Si were demonstrated to be consistently of order 100 ns or longer; desired n- and p-doping levels were achieved; solar cell series specific resistances <10 ?-cm2 were achieved; A single-junction solar cell having a state-of-the-art value of Voc and a unverified 16.4% efficiency was fabricated from CdZnTe having a 1.80 eV bandgap, ideal for the top junction in a tandem cell with a Si bottom junction.
Carmody, M.; Gilmore, A.
Science Conference Proceedings (OSTI)
We report a compact in-line Mach-Zehnder interferometer combining a microtaper with a long-period grating (LPG) in a section of all-solid photonic bandgap fiber. Theoretical and experimental investigations reveal that the interferometer works from the interference between the fundamental core mode and the LP{sub 01} cladding supermodes. The mechanism underlying the mode coupling caused by the microtaper can be attributed to a bandgap-shifting as the fiber diameter is abruptly scaled down. In addition, the interferometer designed to strengthen the coupling ratio of the long-period grating has a promising practical application in the simultaneous measurement of curvature and temperature.
Wu Zhifang [Key Laboratory of Optical Information and Technology, Ministry of Education and Institute of Modern Optics, Nankai University, Tianjin 300071 (China); OPTIMUS, School of Electrical and Electronics Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 637553 (Singapore); Liu Yange; Wang Zhi; Han Tingting; Li Shuo [Key Laboratory of Optical Information and Technology, Ministry of Education and Institute of Modern Optics, Nankai University, Tianjin 300071 (China); Jiang Meng; Ping Shum, Perry [OPTIMUS, School of Electrical and Electronics Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 637553 (Singapore); CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore 637553 (Singapore); Quyen Dinh, Xuan [CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore 637553 (Singapore); Thales Solutions Asia Pte Ltd, R and T Department, 28 Changi North Rise, Singapore 498755 (Singapore)
Investigation of the signature of lung tissue in X-ray grating-based phase-contrast imaging
Purpose: Grating-based X-ray phase-contrast imaging is a promising modality increasing the soft tissue contrast in medical imaging. In this work, the signature of lung tissue in X-ray grating-based physe-contrast imaging is investigated. Methods: We used a Talbot-Lau interferometer for our investigations of two C57BL/6 mice. Both underwent projection imaging and computed tomography. Results: The results show that the three images obtained by X-ray phase-contrast imaging show complementary anatomical structures. Especially the dark field image allows a more-exact determination of the position of the lung in the chest cavity. Conclusion: Due to its sensitivity to granular structures, the dark field image may be used for the diagnosis of lung diseases in earlier stages or without a CT scan. Furthermore, X-ray phase-contrast imaging may also have great potential in the application of animal laboratory sciences to reduce the number of required animals used in long-term translational, toxicity, and regenerative med...
Weber, Thomas; Haas, Wilhelm; Pelzer, Georg; Rieger, Jens; Ritter, Andr�; Wucherer, Lukas; Braun, Jan Matthias; Durst, J�rgen; Michel, Thilo; Anton, Gisela
Electrodeposition of PbTe Thermoelectric Materials in NaOH Solutions
Science Conference Proceedings (OSTI)
Dissolution Kinetics of Steelmaking Slag and Its Promotion for the Growth of Algae � Electrodeposition of PbTe Thermoelectric Materials in NaOH Solutions.
Electrical properties of PbTe single crystals with excess tellurium
Science Conference Proceedings (OSTI)
The effects of excess (up to 0.1 at %) Te atoms and heat treatment at 473 and 573 K for 120 h on the conductivity {sigma}, thermopower {alpha}, and Hall coefficient R of PbTe single crystals are studied. It is shown that excess Te atoms and annealing strongly affect the values and character of the temperature dependences of these parameters and the signs of {alpha} and R at low temperatures, which is caused by the acceptor effect of these atoms and the formation of antisite defects due to localization of Te in vacancies of the lead sublattice upon annealing.
Bagiyeva, G. Z., E-mail: firstname.lastname@example.com; Mustafayev, N. B.; Abdinova, G. Dj.; Abdinov, D. Sh. [National Academy of Sciences of Azerbaijan, Abdullaev Institute of Physics (Azerbaijan)
Characterization of Heterogeneities in Detector-Grade CdZnTe Crystals
Science Conference Proceedings (OSTI)
Synthetic Cd{sub 1-x}ZnxTe or 'CZT' crystals are highly suitable for g-spectrometers operating at room temperature. Secondary phases (SP) within CZT, presumed to be Te metal, have detrimental impacts on the charge collection efficiency of fabricated device. Using analytical techniques rather than arbitrary theoretical definitions, we identify two SP morphologies: (i) many void, 20-{mu}m 'negative' crystals with 65-nm nanoparticle residues of Si, Cd, Zn, and Te and (ii) 20-{mu}m hexagonal-shaped bodies, which are composites of metallic Te layers with cores of amorphous and polycrystalline CZT material that surround the voids.
Duff, M.; Hunter, D; Burger, A; Groza, M; Buliga, V; Bradley, J; Graham, G; Dai, Z; Lanzirotti, A; et. al.
Review of Photovoltaic Energy Production Using CdTe Thin-Film Modules: Extended Abstract Preprint
CdTe has near-optimum bandgap, excellent deposition traits, and leads other technologies in commercial PV module production volume. Better understanding materials properties will accelerate deployment.
Gessert, T. A.
NREL Determines Long-Lived Carriers and Differences in CdTe Superstrat...
NLE Websites -- All DOE Office Websites (Extended Search)
"Comparison of Minority Carrier Lifetime Measurements in Superstrate and Substrate CdTe PV Devices." Proc. 37 th IEEE Photovoltaic Specialists Conference, 19-24 June 2011,...
Mechanical Properties of Thermoelectric Materials PbTe-PbS and ...
Science Conference Proceedings (OSTI)
... thermoelectric (TE) materials for a variety of applications, including the conversion of waste heat energy into electricity. LAST (Lead-Antimony-Silver-
Characterization and Analysis of CIGS and CdTE Solar Cells: December 2004 - July 2008
The work reported here embodies a device-physics approach based on careful measurement and interpretation of data from CIGS and CdTe solar cells.
Sites, J. R.
~~~~: Gmt Lakes Cat-bar) ALTERNaTE I
Office of Legacy Management (LM)
~~~: Gmt Lakes Cat-bar) ~~~: Gmt Lakes Cat-bar) ALTERNaTE I --------------------------------------- NAME: 333 Iv. Mkhi qr) Aw. thka o ~~~---~~~--~~~_-----__ C I TV : 8 Morim 'Love 82 10 bhh &Q Ir -+----------- STATE- fL I - ------ l OWNER(S) -__----_ past: Current: I --------------------____ Owner contacted q yes p no; _____--_____-____------~~~l if yes, data contacted -_--------__- TYPE OF OPERATION ---_------------- 0 Research & Development q Production scale testing 0 Pilot Scale 0 Bench Scale process 0 Theoretical Studies 0 Sample & Analysis Facility Type p Manufacturing I ! fJ University 0 Research Organization ! 0 Government Sponsored F+ci li ty 0 Other ----~~-~~~----~------ 0 Production 0 Disposal/Storage TYPE OF CUNTRKT ----~---~__----_ / w Prime
Multiple charge density wave transitions in Gd2Te5
Science Conference Proceedings (OSTI)
Diffraction measurements performed via transmission electron microscopy and high resolution X-ray scattering reveal two distinct charge density wave transitions in Gd{sub 2}Te{sub 5} at T{sub c1} = 410(3) and T{sub c2} = 532(3) K, associated with the on-axis incommensurate lattice modulation and off-axis commensurate lattice modulation respectively. Analysis of the temperature dependence of the order parameters indicates a non-vanishing coupling between these two distinct CDW states.
Shin, K.Y.; Ru, N.; /Stanford U., Geballe Lab. /Stanford U., Appl. Phys. Dept.; Condron, C.L.; /SLAC, SSRL; Wu, Y.Q.; Kramer, M.J.; Toney, M.F.; /Ames Lab /Iowa State U., Dept. Mater. Sci. /SLAC, SSRL; Fisher, I.R.; /Stanford U., Geballe Lab. /Stanford U., Appl. Phys. Dept.
Conformal and projection diagrams in LaTeX
In general relativity, the causal structure of space-time may sometimes be depicted by conformal Carter-Penrose diagrams or a recent extension of these - the projection diagrams. The introduction of conformal diagrams in the sixties was one of the progenitors of the golden age of relativity. They are the key ingredient of many scientific papers. Unfortunately, drawing them in the form suitable for LaTeX documents is time-consuming and not easy. We present below a library that allows one to draw an arbitrary conformal diagram in a few simple steps.
Christa R. �lz; Sebastian J. Szybka
Simple shear processing of bulk BI?TE? alloys
The objective of this work is to determine the appropriate extrusion conditions of cast Bi?Te? alloys via equal channel angular extrusion (ECAE) to produce material that has a fine grain size (5~30[]m), uniform grain morphology and low grain boundary misorientation for improving thermoelectric and mechanical properties. The range of variables examined in this study includes: alloy type (p- and n-type) extrusion temperature (400 ~ 525?C), extrusion route (A, B, C and E), extrusion speed (0.3 ~ 0.01 in/min), and the number of extrusions (1, 2, 4 and 8). The microstructure is characterized by a polarized optical microscopy. Successful extrusions were accomplished at a temperature and strain rate that enabled dynamic recrystallization. Holding in the hot die after extrusion encouraged grain growth. The post processed grain size is found to be strongly dependent on extrusion temperature and extrusion speed. The microstructural uniformity is found to be dependent on the number of extrusions and extrusion route. Uniform equiaxial grain of 10 to 30mm average size are obtained in the p-type alloy after four extrusion passes following route E at a temperature of 500?C and an extrusion speed of 0.1 in/min. The results encourage further work and indicate ECAE is a viable method of grain refinement of Bi?Te? alloys.
Im, Jae-taek
Advanced CdTe Photovoltaic Technology: September 2007 - March 2009
During the last eighteen months, Abound Solar (formerly AVA Solar) has enjoyed significant success under the SAI program. During this time, a fully automated manufacturing line has been developed, fabricated and commissioned in Longmont, Colorado. The facility is fully integrated, converting glass and semiconductor materials into complete modules beneath its roof. At capacity, a glass panel will enter the factory every 10 seconds and emerge as a completed module two hours later. This facility is currently undergoing trials in preparation for large volume production of 120 x 60 cm thin film CdTe modules. Preceding the development of the large volume manufacturing capability, Abound Solar demonstrated long duration processing with excellent materials utilization for the manufacture of high efficiency 42 cm square modules. Abound Solar prototype modules have been measured with over 9% aperture area efficiency by NREL. Abound Solar demonstrated the ability to produce modules at industry leading low costs to NREL representatives. Costing models show manufacturing costs below $1/Watt and capital equipment costs below $1.50 per watt of annual manufacturing capacity. Under this SAI program, Abound Solar supported a significant research and development program at Colorado State University. The CSU team continues to make progress on device and materials analysis. Modeling for increased device performance and the effects of processing conditions on properties of CdTe PV were investigated.
Barth, K.
Search for Short Duration Bursts of TeV Gamma Rays with the Milagrito Telescope
OG 2.3.07 Search for Short Duration Bursts of TeV Gamma Rays with the Milagrito Telescope Gus for short duration bursts of TeV photons. Such bursts may result from "traditional" gamma-ray bursts to gamma-ray bursts, the final stages of black hole evaporation) the most compelling reason may
California at Santa Cruz, University of
Charge transport in mixed CdSe and CdTe colloidal nanocrystal films
We report the influence of trap states on charge transport through films of mixed CdTe and CdSe nanocrystals (NCs) between lateral electrodes, through layered films of CdTe and CdSe NCs in a layered geometry, and through ...
Bawendi, Moungi G.
A Search for TeV Emission from Active Galaxies using the Milagro Observatory
: Professor Gregory W. Sullivan, Chairman/Advisor Professor Jordan A. Goodman Professor Rabindra N. Mohapatra that observes very high energy gamma rays (100 GeV to 100 TeV) using the water-Cerenkov techniqueV candidates. Active galaxies have been observed to be highly variable at TeV energies. To test for episodic
California at Santa Cruz, University of
Effects of Surface Composition on CdTe/CdS Device Performance
The atomic composition of the back surface of the CdTe layer in a CdTe/CdS photovoltiac (PV) device has a significant influence on the quality of the electrical contact to this layer. This paper reports the results of a systematic study that correlates the composition of the back surface with pre-contact processing and device performance.
Levi, D.; Albin, D.; King, D.
Fabrication and Physics of CdTe Devices by Sputtering: Final Report, 1 March 2005 - 30 November 2008
Work to understand CdS/CdTe solar cell device physics; increase magnetron sputtering rate (while keeping high device quality); reduce thickness of CdTe layers (while keeping voltage and fill factor).
Compaan, A.; Collins, R.; Karpov, V.; Giolando, D.
Distributed fault management in WBEM-Based Inter-AS TE for qos guaranteed DiffServ-over�MPLS
Science Conference Proceedings (OSTI)
Distributed fault management and event notification are essential in Inter-AS Traffic Engineering (TE). In this paper we design and implement distributed fault management for WBEM based inter-AS TE. We designed DMTF Managed Object Format (MOF) based ...
Abdurakhmon Abdurakhmanov; Shahnaza Tursunova; Shanmugham Sundaram; Young-Tak Kim
Health and environmental hazards of CdTe photovoltaic module production, use and decommissioning
Health and environmental (H&E) risks presented by CdTe photovoltaic module production, use and decommissioning have been reviewed and discussed by several authors. Several H&E concerns exit. The estimated risks are based on extrapolations of toxicity, environmental mobility, and bioavailability data for other inorganic cadmium compounds. Little information, however, is available about CdTe itself. In response to the increased interest in CdTe, Brookhaven National Laboratory (BNL) has been engaged in a cooperative research program with the National Institute of Environmental Health Sciences (NIEHS), the Fraunhofer Institute for Solid State Technology (IFT), and the GSF Institute of Chemical Ecology to develop fundamental toxicological and environmental data for CdTe. This paper describes the results of these studies, and their potential implications with respect to the H&E hazards presented by CdTe module production, use and decommissioning.
Moskowitz, P.D. [Brookhaven National Lab., Upton, NY (United States); Steinberger, H. [Fraunhofer Institut fur Festkorpertechnologie, Munchen (Germany); Thumm, W. [GSF-Institute of Ecological Chemistry, Oberschleissheim (Germany)
Phase formation and phase transformations in Bi-Te films with nanoscale thickness
Science Conference Proceedings (OSTI)
The processes of phase formation are studied in a binary Bi-Te system using the kinematic electron diffraction technique. It is established that, in the case of both simultaneous and layer-by-layer deposition of bismuth and tellurium and irrespective of the order of their deposition, phases with compositions Bi{sub 2}Te{sub 3} and BiTe are formed at the condensation plane in the amorphous and crystalline state, respectively. The amorphous Bi{sub 2}Te{sub 3} phase is stable at room temperature and crystallizes at a temperature of 423 K. It is shown that ordering of the phase BiTe is not a consequence of atomic order of the structure; rather, it is caused by the real structure of the object (by blocks)
Akhmedov, K. M. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)], E-mail: firstname.lastname@example.com
Te Inclusions in CZT Detectors: New Method for Correcting Their Adverse Effects
Science Conference Proceedings (OSTI)
Both Te inclusions and point defects can trap the charge carriers generated by ionizing particles in CdZnTe (CZT) detectors. The amount of charge trapped by point defects is proportional to the carriers� drift time and can be corrected electronically. In the case of Te inclusions, the charge loss depends upon their random locations with respect to the electron cloud. Consequently, inclusions introduce fluctuations in the charge signals, which cannot be easily corrected. In this paper, we describe direct measurements of the cumulative effect of Te inclusions and its influence on the response of CZT detectors of different thicknesses and different sizes and concentrations of Te inclusions. We also discuss a means of partially correcting their adverse effects.
Bolotnikov, A.E.; Babalola, S.; Camarda, G.S.; Cui, Y.; Egarievwe, S.U.; Hawrami, R.; Hossain, A.; Yang, G.; James, R.B.
Te Inclusions in CZT Detectors: New Method for Correcting Their Adverse Effects
Science Conference Proceedings (OSTI)
Both Te inclusions and point defects can trap the charge carriers generated by ionizing particles in CdZnTe (CZT) detectors. The amount of charge trapped by point defects is proportional to the carriers' drift time and can be corrected electronically. In the case of Te inclusions, the charge loss depends upon their random locations with respect to the electron cloud. Consequently, inclusions introduce fluctuations in the charge signals, which cannot be easily corrected. In this paper, we describe direct measurements of the cumulative effect of Te inclusions and its influence on the response of CZT detectors of different thicknesses and different sizes and concentrations of Te inclusions. We also discuss a means of partially correcting their adverse effects.
Bolotnikov, A.; Babaloa, S; Camarda, G; Cui, Y; Egarievwe, S; Hawrami, R; Hossain, A; Yang, G; James, R
V-183: Cisco TelePresence TC and TE Bugs Let Remote Users Deny Service and
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
3: Cisco TelePresence TC and TE Bugs Let Remote Users Deny 3: Cisco TelePresence TC and TE Bugs Let Remote Users Deny Service and Remote Adjacent Authenticated Users Gain Root Shell Access V-183: Cisco TelePresence TC and TE Bugs Let Remote Users Deny Service and Remote Adjacent Authenticated Users Gain Root Shell Access June 21, 2013 - 6:00am Addthis PROBLEM: Three vulnerabilities were reported in Cisco TelePresence TC and TE PLATFORM: The following product models are affected by the vulnerabilities: Cisco TelePresence MX Series Cisco TelePresence System EX Series Cisco TelePresence Integrator C Series Cisco TelePresence Profiles Series running Cisco TelePresence Quick Set Series Cisco IP Video Phone E20 ABSTRACT: Cisco TelePresence TC and TE Software contain two vulnerabilities in the implementation of the Session Initiation Protocol (SIP) that could allow an
The objective of the Junction Studies are: (1) understand the nature of the junction in the CdTe/CdS device; (2) correlate the device fabrication parameters to the junction formation; and (3) develop a self consistent device model to explain the device properties. Detailed analysis of CdS/CdTe and SnO{sub 2}/CdTe devices prepared using CSS CdTe is discussed.
Dhere, R. G.; Zhang, Y.; Romero, M. J.; Asher, S. E.; Young, M.; To, B.; Noufi, R.; Gessert, T. A.
The goal of this work was to evaluate different CdTe feedstock formulations (feedstock provided by Redlen) to determine if they would significantly improve CdTe performance with ancillary benefits associated with whether changes in feedstock would affect CdTe cell processing and possibly reliability of cells. Feedstock also included attempts to intentionally dope the CdTe with pre-selected elements.
Albin, D.
Spin diffusion in n-GaAs quantum wells, as measured by our optical transient-grating technique, is strongly suppressed relative to that of charge. Over a broad range of temperatures and dopings, the suppression of Ds relative to Dc agrees quantitatively with the prediction of ''spin Coulomb dra'' theory, which takes into account the exchange of spin in electron-electron collisions. Moreover, the spin-diffusion length, Ls, is a nearly constant 1 micrometer over the same range of T and n, despite Ds's varying by nearly two orders of magnitude. This constancy supports the D'yakonov-Perel'-Kachorovskii model of spin relaxation through interrupted precessional dephasing in the spin-orbit field.
Weber, Christopher P.
In the course of analyzing the axiomatic principles that form the basis of statistical physics, the validity of the postulate that all the isoenergetic microstates of a closed system are equally probable was checked. This article reports the results of numerically modelling the interaction of thermodynamically equilibrium blackbody radiation with a reflective phase diffraction grating that possesses ideal conductivity. Cases are found in which anisotropy of the polarization parameters is guaranteed to appear inside a closed volume of initially homogeneous blackbody radiation, resulting in a formal decrease of its Boltzmann entropy as a consequence of deviation from the microcanonical Gibbs distribution. This is apparently caused by the discontinuous character of the change of the phase trajectories of the photons during diffraction, which makes the physical system under consideration nonergodic.
Savukov, Vladimir V
Vibrational signatures of OTe and OTe-VCd in CdTe: A first principles study
Science Conference Proceedings (OSTI)
Chen et al. [Phys. Rev. Lett. 96 (2006) 035508] experimentally observed vibrational signatures related to defects in oxygen-doped CdTe using ultrahigh resolution Fourier transform infrared (FTIR) spectroscopy. They observed an absorption peak at 350 cm{sup -1}. In addition, for samples grown under certain conditions, they observed two higher frequency peaks (1097 and 1108 cm{sup -1}) at low temperature that merged into one at room-temperature. They attributed the low-frequency peak (350 cm{sup -1}) to the vibration of O{sub Te} and the two higher frequency peaks to the vibrational modes of a O{sub Te}-V{sub Cd} complex. Subsequently, they reported similar modes around 1100 cm{sup -1} in O-doped CdSe [Phys. Rev. Lett. 101 (2008) 195502] which were attributed to an O{sub Se}-V{sub Cd} complex. We employed first-principles DFT calculations to calculate the vibrational modes of O{sub Te} and O{sub Te}-V{sub Cd} complex in CdTe. Our calculations show that the 350 cm{sup -1} mode is consistent with O{sub Te}. However, the frequencies of the modes around 1100 cm{sup -1} are more than twice the expected frequencies for O{sub Te}-V{sub Cd} complexes in CdTe (or O{sub Se}-V{sub Cd} in CdSe), indicating that the O{sub Te}-V{sub Cd} complex cannot be the cause of the observed 1100 cm{sup -1} modes. A search for a new defect model is in order.
Thienprasert, J.T. [Kasetsart University, Thailand; Limpijumnong, Sukit [Kasetsart University, Thailand; Janotti, Anderson [University of California, Santa Barbara; Van de Walle, C.G. [University of California, Santa Barbara; Zhang, Lijun [ORNL; Du, Mao-Hua [ORNL; Singh, David J [ORNL
A GENERAL RELATIVISTIC EXTERNAL COMPTON-SCATTERING MODEL FOR TeV EMISSION FROM M87
M87 is the first detected non-blazar extragalactic tera-electron-volt (TeV) source with rapid variation and a very flat spectrum in the TeV band. To explain the two peaks in the spectral energy distribution of the nucleus of M87, which is similar to that of blazars, the most commonly adopted models are the synchrotron self-Compton-scattering models and the external inverse Compton (EIC) scattering models. Considering that there is no correlated variation in the soft band (from radio to X-ray) matching the TeV variation and that the TeV sources should not suffer from {gamma}{gamma} absorption due to the flat TeV spectrum, the EIC models are advantageous in modeling the TeV emission from M87. In this paper, we propose a self-consistent EIC model to explain the flat TeV spectrum of M87 within the framework of fully general relativity, where the background soft photons are from the advection-dominated accretion flow around the central black hole, and the high-energy electrons are from the mini-jets that are powered by the magnetic reconnection in the main jet. In our model, both the TeV flares observed in the years 2005 and 2008 could be well explained: the {gamma}{gamma} absorption for TeV photons is very low, even inside the region very close to the black hole 20R{sub g} {approx} 50R{sub g} ; at the same region, the average EIC cooling time ({approx}10{sup 2} {approx} 10{sup 3} s) is short, which is consistent with the observed timescale of the TeV variation. Furthermore, we also discuss the possibility that the accompanying X-ray flare in 2008 is due to the direct synchrotron radiation of the mini-jets.
Cui Yudong; Yuan Yefei [Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Sciences and Technology of China, CAS, Hefei, Anhui 230026 (China); Li Yanrong; Wang Jianmin, E-mail: firstname.lastname@example.com [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, CAS, 19B Yuquan Road, Beijing 100049 (China)
A multilayer mirror with a novel layer structure to uniformly enhance the reflectivity in a few keV energy range at a fixed angle of incidence is invented and applied to a multilayer grating for use in a flat-field spectrograph attached to a conventional electron microscope. The diffraction efficiency of the fabricated multilayer grating having the new layer structure is evaluated at the angle of incidence of 88.65 deg. in the energy region of 2.1-4.0 keV. It is shown that the multilayer grating is effective to uniformly enhance the diffraction efficiency and able to be practically used in this energy region.
Imazono, T.; Koike, M.; Koeda, M.; Nagano, T.; Sasai, H.; Oue, Y.; Yonezawa, Z.; Kuramoto, S.; Terauchi, M.; Takahashi, H.; Handa, N.; Murano, T. [QuBS, Japan Atomic Energy Agency (JAEA), 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Device Dept., Shimadzu Corp., 1 Nishinokyo-Kuwabarcho, Nakagyo-ku, Kyoto 604-8511 (Japan); IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); EC Business Unit, JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan)
Plasma graviton production in TeV-scale gravity
We develop the theory of interaction of classical plasma with Kaluza-Klein (KK) gravitons in the ADD model of TeV-scale gravity. Plasma is described within the kinetic approach as the system of charged particles and Maxwell field both confined on the brane. Interaction with multidimensional gravity living in the bulk with $n$ compact extra dimensions is introduced within the linearized theory. The KK gravitons emission rates are computed taking into account plasma collective effects through the two-point correlation functions of the fluctuations of the plasma energy-momentum tensor. Apart from known mechanisms (such as bremsstrahlung and gravi-Primakoff effect) we find essentially collective channels such as the coalescence of plasma waves into gravitons which may be manifest in turbulent plasmas. Our results indicate that commonly used rates of the KK gravitons production in stars and supernovae may be underestimated.
E. Yu. Melkumova
Additional Characterization of Min-K TE-1400 Thermal Insulation
Science Conference Proceedings (OSTI)
Min-K 1400TE (Thermal Ceramics, Augusta, Georgia) insulation material was further characterized at Oak Ridge National Laboratory (ORNL) for use in structural applications under gradient temperature conditions in an inert environment. Original characterization of Min-K was undertaken from April 1997 to July 2008 to determine its high temperature compressive strength and stress relaxation behavior up to 900 C in helium along with the formulation of a general model for the mechanical behavior exhibited by Min-K under these conditions. The additional testing described in this report was undertaken from April 2009 to June 2010 in an effort to further evaluate the mechanical behavior of Min-K when subjected to a variety of conditions including alternative test temperatures and time scales than previously measured. The behavior of Min-K under changing environments (temperature and strain), lateral loads, and additional isothermal temperatures was therefore explored.
Hemrick, James Gordon [ORNL; King, James [ORNL
Most work on CdTe-based solar cells has focused on devices with a superstrate structure. This focus is due to the early success of the superstrate structure in producing high-efficiency cells, problems of suitable ohmic contacts for lightly doped CdTe, and the simplicity of the structure for manufacturing. The development of the CdCl2 heat treatment boosted CdTe technology and perpetuated the use of the superstrate structure. However, despite the beneficial attributes of the superstrate structure, devices with a substrate structure are attractive both commercially and scientifically. The substrate structure eliminates the need for transparent superstrates and thus allows the use of flexible metal and possibly plastic substrates. From a scientific perspective, it allows better control in forming the junction and direct access to the junction for detailed analysis. Research on such devices has been limited. The efficiency of these devices has been limited to around 8% due to low open-circuit voltage (Voc) and fill factor. In this paper, we present our recent device development efforts at NREL on substrate-structure CdTe devices. We have found that processing parameters required to fabricate high-efficiency substrate CdTe PV devices differ from those necessary for traditional superstrate CdTe devices. We have worked on a variety of contact materials including Cu-doped ZnTe and CuxTe. We will present a comparative analysis of the performance of these contacts. In addition, we have studied the influence of fabrication parameters on junction properties. We will present an overview of our development work, which has led to CdTe devices with Voc values of more than 860 mV and NREL-confirmed efficiencies approaching 11%.
Dhere, R. G.; Duenow, J. N.; DeHart, C. M.; Li, J. V.; Kuciauskas, D.; Gessert, T. A.
Light-Induced Tellurium Enrichment on CdZnTe Crystal Surfaces Detected by Raman Spectroscopy
Science Conference Proceedings (OSTI)
CdZnTe (CZT) crystals can be grown under controlled conditions to produce high-quality crystals to be used as room-temperature radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect the crystal's performance. In this study, CZT crystals were analyzed by micro-Raman spectroscopy. The growth of Te rich areas on the surface was induced by low-power lasers. The growth was observed versus time with low-power Raman scattering and was observed immediately under higher-power conditions. The detector response was also measured after induced Te enrichment.
Hawkins, Samantha A.; Villa-Aleman, Eliel; Duff, Martine C.; Hunter, Doug B.; Burger, Arnold; Groza, Michael; Buliga, Vladimir; Black, David R. (SRNL); (NIST); (Fisk U)
POLARIZATION STUDIES OF CdZnTe DETECTORS USING SYNCHROTRON X-RAY RADIATION.
Science Conference Proceedings (OSTI)
New results on the effects of small-scale defects on the charge-carrier transport in single-crystal CdZnTe (CZT) material were produced. We conducted detailed studies of the role of Te inclusions in CZT by employing a highly collimated synchrotron x-ray radiation source available at Brookhaven's National Synchrotron Light Source (NSLS). We were able to induce polarization effects by irradiating specific areas with the detector. These measurements allowed the first quantitative comparison between areas that are free of Te inclusions and those with a relatively high concentration of inclusions. The results of these polaration studies will be reported.
Chapter 1.19: Cadmium Telluride Photovoltaic Thin Film: CdTe
Science Conference Proceedings (OSTI)
The chapter reviews the history, development, and present processes used to fabricate thin-film, CdTe-based photovoltaic (PV) devices. It is intended for readers who are generally familiar with the operation and material aspects of PV devices but desire a deeper understanding of the process sequences used in CdTe PV technology. The discussion identifies why certain processes may have commercial production advantages and how the various process steps can interact with each other to affect device performance and reliability. The chapter concludes with a discussion of considerations of large-area CdTe PV deployment including issues related to material availability and energy-payback time.
Gessert, T. A.
Recent results from the Milagro TeV gamma-ray observatory
Milagro is a gamma-ray observatory employing a water Cherenkov detector to observe extensive air showers produced by high-energy particles impacting in the Earth's atmosphere. We discuss the first detection of TeV gamma-rays from the Galactic plane and report the detection of an extended TeV source coincident with the EGRET source 3EG J0520+2556, and the observation of TeV emission from the Cygnus region of our Galaxy. We also summarize the status of our search for Very High Energy (VHE) emission from satellite-triggered Gamma Ray Bursts (GRBs) and discuss plans for the next generation water Cherenkov detector.
Parkinson, P M S
Thin-film CdTe and CuInSe{sub 2} photovoltaic technologies
Total-area conversion efficiency of 15%--15.8% have been achieved for thin-film CdTe and CIS solar cells. Modules with power output of 5--53 W have been demonstrated by several groups world-wide. Critical processes and reaction pathways for achieving excellent PV devices have been eluciated. Research, development and technical issues have been identified, which could result in potential improvements in device and module performance. A 1-kW thin-film CdTe array has been installed and is being tested. Multimegawatt thin-film CdTe manufacturing plants are expected to be completed in 1-2 years.
Ullal, H.S.; Zweibel, K.; von Roedern, B.G.
XPS and AES Studies of Cu/CdTe(111)-B
Copper is frequently used as a p-type dopant to improve the performance of back contacts in CdTe thin-film solar cells. In this study, surface-analysis techniques are used to probe fundamental interactions between Cu and the CdTe(111)-B surface. The results presented here were facilitated by the newly constructed surface-analysis cluster tool in the Measurements and Characterization Division at NREL; they reveal a host of fundamental phenomena that occur in the Cu/CdTe system.
Teeter, G.; Gessert, T. A.; Asher, S. E.
Spectroscopy of low energy solar neutrinos using CdTe detectors
The usage of a large amount of CdTe(CdZnTe) semiconductor detectors for solar neutrino spectroscopy in the low energy region is investigated. Several different coincidence signals can be formed on five different isotopes to measure the Be-7 neutrino line at 862 keV in real-time. The most promising one is the usage of Cd-116 resulting in 89 SNU. The presence of Te-125 permits even the real-time detection of pp-neutrinos. A possible antineutrino flux above 713 keV might be detected by capture on Cd-106 .
K. Zuber
Spectroscopy of low energy solar neutrinos using CdTe detectors
The usage of a large amount of CdTe(CdZnTe) semiconductor detectors for solar neutrino spectroscopy in the low energy region is investigated. Several different coincidence signals can be formed on five different isotopes to measure the Be-7 neutrino line at 862 keV in real-time. The most promising one is the usage of Cd-116 resulting in 89 SNU. The presence of Te-125 permits even the real-time detection of pp-neutrinos. A possible antineutrino flux above 713 keV might be detected by capture on Cd-106 .
Zuber, K
During the first quarter of this contract, facilities for the spray pyrolysis deposition of CdTe thin films using a process anolagous to that used to spray deposit device-quality films of CdS were prepared. A Te salt, ..beta..-(CH/sub 3/)/sub 2/TeI/sub 2/, suitable for use in the spray process was synthesized. The facilities were shown to function properly by the successful spraying of good quality CdS thin films. A number of initial spray experiments were conducted utilizing the ..beta..-(CH/sub 3/)/sub 2/TeI/sub 2/ and other inorganic tellurium-bearing compounds which also show great promise in producing low-cost sprayed CdTe solar cells. Initial chemical tests of these films indicated the presence of both Cd and Te, and x-ray diffraction analysis is presently underway to determine the actual concentration of CdTe.
Sienkiewicz, P.; Lis, S.; Serreze, H.B.; Entine, G.
An x-ray grating spectrometer was built in order to measure opacities in the 50 eV to 250 eV spectral range with an average spectral resolution
Reverdin, Charles; Caillaud, T.; Gilleron, F.; Pain, J. C.; Silvert, V.; Soullie, G.; Villette, B. [CEA, DAM, DIF, 91297 Arpajon (France); Thais, Frederic; Loisel, Guillaume; Blenski, T.; Poirier, M. [CEA, DSM, IRAMIS, Service Photons, Atomes et Molecules, 91191 Gif-sur-Yvette (France); Busquet, M. [ARTEP Inc, Ellicott City, Maryland 21042 (United States); Bastiani-Ceccotti, S.; Serres, F. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France); Ducret, J. E. [CELIA, UMR5107, CEA, CNRS, Universite de Bordeaux, 33400 Talence (France); Foelsner, W. [Max Planck Instituet fuer Quantum Optik, 85748 Garching (Germany); Gilles, D.; Turck-Chieze, S. [CEA, DSM, IRFU, Service d'astrophysique, 91191 Gif-sur-Yvette (France)
We studied the possibility of controlling phase-locked lasing of a set of lasers with self-pumped phase-conjugate gain-grating mirrors by using a passive Q-switch and selecting the gain of one of the lasers. The ranges of stable operation are calculated by mathematical simulation and well agree with the experimental results. Single-mode radiation in the form of trains of phase-locked laser pulses are experimentally obtained for the first time in a three-channel diffraction-coupled gain-grating Nd : YAG laser system with a LiF :F {sup -}{sub 2} passive Q-switch. The space-time pattern of the trains of 1.064-{mu}m nanosecond pulses is the same in the channels with and without Q-switch and their interference pattern contrast reaches 0.81. (control of laser radiation parameters)
Basiev, Tasoltan T; Gavrilov, A V; Smetanin, Sergei N; Fedin, Aleksandr V
Science Conference Proceedings (OSTI)
We studied selective etching and polymer deposition in submicrometer pitch gratings on the surface of InP using reactive ion etching with methane and hydrogen and investigated the plasma condition dependence of the selectivity. Using a mask structure consisting of regions with and without a thick layer on a grating-patterned thin layer, we achieved selective etching in submicrometer pitch gratings. In experiments conducted on the same surface at the same time, the InP is selectively etched in the window of the grating in the region with the thick layer, but it is not etched, and polymer is deposited, in the window of the grating in the region without the thick layer. We found that the selectivity depends on the plasma conditions, such as the hydrogen flow rate, pressure, and plasma power in reactive ion etching. This dependence might result from the variation in the ionic atoms of hydrogen or hydrocarbon/hydrogen, which are attracted to the charged mask and supplied to the window of the grating.
Yamamoto, Norio
Science Conference Proceedings (OSTI)
We have been developing a wavelength-dispersive soft x-ray spectrograph covering an energy region of 50-4000 eV to attach to a conventional electron microscope. Observation of soft x-ray emission in the 2-4 keV range needs a multilayer coated grating. In order to evaluate the performance of the optical component in the energy region, a goniometric apparatus has been newly developed and the preliminary performance has been tested using synchrotron radiation.
Imazono, Takashi; Koike, Masato; Kawachi, Tetsuya; Hasegawa, Noboru; Koeda, Masaru; Nagano, Tetsuya; Sasai, Hiroyuki; Oue, Yuki; Yonezawa, Zeno; Kuramoto, Satoshi; Terauchi, Masami; Takahashi, Hideyuki; Handa, Nobuo; Murano, Takanori [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Device Dept., Shimadzu Corp., 1 Nishinokyo-Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511 (Japan); IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); ECBU, JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan)
Appendix B: CArBon dioxide CApture teChnology SheetS
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teChnology uPDate, may 2013 eleCtroChemiCal membrane for Carbon DioxiDe CaPture & Power generation primary project goals FuelCell Energy, Inc. (FCE) is developing an...
Cd1-xMnxTe semimagnetic semiconductors for ultrafast spintronics and magnetooptics
Science Conference Proceedings (OSTI)
We present ultrafast optical characterization of Cd1-xMnxTe single crystals with high (x>0.5-Mn) concentration, studied by magnetooptical sampling and time-resolved magnetization modulation spectroscopy. We have demonstrated that ...
R. Rey-de-Castro; Daozhi Wang; A. Verevkin; A. Mycielski; R. Sobolewski
Science Conference Proceedings (OSTI)
Telluride (CdTe) is a front-runner photovoltaic (PV) material because it has already attained efficiencies above 16%. The fabrication of CdTe nanoparticles has aroused considerable interest because of their potential application as active layer in organic/inorganic hybrid solar cells. They can also be used for sensitisation of wide band gap semiconductors. In this work, we explore pulsed electron beam deposition (PED) technique to fabricate CdTe nanoparticles. Two ablation parameters, namely background gas pressure and electron energy were varied to investigate their effects on the nanoparticle formation. AFM and optical transmission measurements indicate that we have fabricated CdTe nanocrystalline films exhibiting quantum confinement effect. These films contain scattered nanoparticles with diameters varying from 40 nm to 500 nm, which contribute to the optical absorption near the bulk bandgap energy. However, increasing the background pressure to 19 mTorr improves the nanocrystalline film uniformity.
Jackson, E.; Aga, R. Jr.; Steigerwald, A.; Ueda, A.; Pan, Z.; Collins, W. E.; Mu, R. [Department of Physics, Fisk University, 1000 17th Ave N, Nashville TN 37208 (United States)
Z' Bosons, the NuTeV Anomaly, and the Higgs Boson Mass
NuTeV Anomaly, and the Higgs Boson Mass Michael S. Chanowitzpredicted value of the Higgs boson mass, from ? 60 to ? 120from an increase in the Higgs boson mass. There is a vast
Chanowitz, Michael S
Processing Effects on Junction Interdiffusion in CdS/CdTe Polycrystalline Devices
The performance of CdS/CdTe solar cells is strongly impacted by the process used to grow the CdS layer. CdS films grown by chemical-bath deposition (CBD) exhibit lower sublimation (CSS).
Albin, D.; Yan, Y.; King, D.; Moutinho, H.; Jones, K.; Matson, R.; Al-Jassim, M.
ZB/WZ Band Offsets and Carrier Localization in CdTe Solar Cells
Using the first principles band-structure method, we studied systematically the stability and electronic structure of CdX (X=S, Se, and Te) semiconductors with the zinc-blende (ZB) and wurtzite (WZ) crystal structures.
Wei, S.-H.; Zhang, S. B.
Mechanical properties of highly oriented FeSe0.5Te0.5 superconductor
Science Conference Proceedings (OSTI)
We have synthesized highly oriented samples of the superconducting compound FeSe0.5Te0.5 and investigated its mechanical properties. These samples were characterized by scanning electron microscopy(SEM) with energy-dispersive analysis
Jorge Luiz Pimentel J�nior; Paulo Pureur; Cristiano Santos Lopes; Francisco Carlos Serbena; Carlos Eug�nio Foerster; Simone Aparecida da Silva; Alcione Roberto Jurelo; Adilson Luiz Chinelatto
Glass-like thermal transport in AgSbTe2 | ORNL
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Glass-like thermal transport in AgSbTe2: nano-scale insights to improve thermoelectric efficiency May 16, 2013 Inelastic neutron scattering data showing the phonon dispersions...
Low-cost CdZnTe devices for cascade cell application
This report describes a research program to develop a low-cost technique for producing Cd{sub 1-x}Zn{sub x}Te devices for cascade solar cell applications. The technique involves a two-stage process for fabricating such devices with a band gap of about 1.7 eV and a transparent contact layer of low-resistivity ZnTe. In the first stage, thin films of Cd, Zn, and Te are deposited in stacked layers as Cd{sub 1-x}An{sub x}Te. The second stage involves hearing and reacting the layers to form the compound. At first, electrodeposition was used for depositing the layers to successfully fabricate Dc{sub 1-x}Zn{sub x}Te thin-film devices. These films were also intrinsically doped with copper. For the first time, transparent ZnTe films of low resistivity were obtained in a two-stage process; preliminary solar cells using films with low Zn content were demonstrated. A second phase of the project involved growing films with higher Zn content (>15%). Such films were grown on CdS-coated substrates for fabricating devices. The effects of the solar-cell processing steps on the Cd{sub 1-x}Zn{sub x}Te and CdS/Cd{sub 1-x}Zn{sub x}Te interfaces were studied; results showed that the nature of the interface depended on the stoichiometry of the Cd{sub 1-x}Zn{sub x}Te thin film. A sharp interface was observed for the CdS/CdTe structures, but the interface became highly diffused as the Zn content in the absorber layer increased above 15%. The interaction between the CdS window layer and the Cd{sub 1-x}Zn{sub x}Te absorber layer was found to result from an exchange reaction between Zn in the absorber layer and the thin CdS film. 14 refs., 10 figs.
Basol, B.M.; Kapur, V.K. (International Solar Electric Technology, Inglewood, CA (USA))
Deformation and shape transitions in hot rotating neutron deficient Te isotopes
Evolution of the nuclear shapes and deformations under the influence of temperature and rotation is investigated in Te isotopes with neutron number ranging from the proton drip line to the stability valley. Spin dependent critical temperatures for the shape transitions in Te nuclei are computed. Shape transitions from prolate at low temperature and spin to oblate via triaxiality are seen with increasing neutron number and spin.
Aggarwal, Mamta [UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Mumbai 400 098 (India); Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India); Mazumdar, I. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India)
Films of n-type CdTe:In have been deposited by hot-wall vacuum evaporation (HWVE) on 7059 glass substrates, BaF/sub 2/ single crystal substrates, metal (Pt, Cr, Mo, Al) coated glass substrates, and single crystal p-type CdTe substrates. Films deposited on 7059 glass show typically a dark resistivity of 2 x 10/sup 5/ ohm-cm and a light resistivity of 3 x 10/sup 2/ ohm-cm. With increasing In source temperature, the resistivity decreases, but actually increases slightly again if the T/sub In/ is raised above 600/sup 0/C. Photoexcitation increases the electron density but does not affect the electron mobility. It appears that the grains are depleted in the dark. Films deposited on BaF/sup 2/ show dark resistivity of about 5 ohm-cm and light resistivity of about 2 ohm-cm, corresponding to electron densities of about 3 x 10/sup 16/ cm/sup -3/ and electron mobilities of about 30 cm/sup 2//V-sec. For doping levels abpove 10/sup 16/ cm/sup -3/ photoexcitation increases the mobility, but not the electron density; it appears that the grains are not depleted in the dark in this case. Cr coated 7059 glass makes an ohmic contact to n-type CdTe films. A Schottky diode formed with a 100A thick Au layer showed V/sub oc/ = 0.46 V, J/sub sc/ = 9 mA/cm/sup 2/ and a solar efficiency of about 2%. An n/p homojunction device was made by HWVE deposition of a 1.5 ..mu..m thick n-type CdTe layer on a p-type CdTe single crystal substrate. Values of V/sub oc/ = 0.73 V and J/sub sc/ = 0.24 mA/cm/sup 2/ were obtained. Grain boundary investigations showed the additive quality of two independent grain boundaries when measured in series, and tested the effects of passivation by Au, Cu, Li and H/sub 2/ in p-type CdTe grain boundaries, and In in n-type CdTe grain boundaries. Marked decreases in grain boundary resistance were observed after Li diffusion and H/sub 2/ diffusion in p-type CdTe.
Bube, R H
The hot-wall vacuum evaporation system is nearly complete and the first films are expected in early December. CdTe homojunction cells were theoretically modelled and to some extent tested experimentally using the n-type CdTe film on p-type CdTe crystal homojunction cells previously deposited at Linz. Modelling emphasizes the known importance of surface recombination velocity for such homojunction cells. The n-type layer on the experimental cell was thinned by etching from 5 micrometers to 1.5 micrometers, with a corresponding increase in short-circuit current from 0.1 to 1 mA/cm/sup 2/. This behavior is as theoretically expected; to obtain a short-circuit current of 11 mA/cm/sup 2/, as required for a 10% cell, requires a thickness of about 0.2 micrometers for a surface recombination velocity of 10/sup 6/ cm/sec and other realistic cell parameters. By doping experiments on single crystal CdTe, it has been shown that the hole density does decrease when the P dopant density is decreased below a critical value in CdTe:P crystals, thus eliminating the possibility that the major acceptors in the P-doped crystals were not P impurity. Attempts to heavily dope CdTe with As were less successful, but this may be due to the use of elemental As as the dopant in this case rather than a compound of the dopant. Cs was shown to be an effective dopant of CdTe and resistivities as low as 0.3 ohm-cm corresponding to hole densities in the low 10/sup 17/ cm/sup -3/ range were obtained. An apparent correlation between the low-temperature barrier height associated with a grain boundary in CdTe and the angle of mismatch between the two grains has been observed. Improved capacitance of grain boundary measurements should yield defect densities.
Bube, R H
Oxygen Incorporation During Fabrication of Substrate CdTe Photovoltaic Devices: Preprint
Recently, CdTe photovoltaic (PV) devices fabricated in the nonstandard substrate configuration have attracted increasing interest because of their potential compatibility with flexible substrates such as metal foils and polymer films. This compatibility could lead to the suitability of CdTe for roll-to-roll processing and building-integrated PV. Currently, however, the efficiencies of substrate CdTe devices reported in the literature are significantly lower ({approx}6%-8%) than those of high-performance superstrate devices ({approx}17%) because of significantly lower open-circuit voltage (Voc) and fill factor (FF). In our recent device development efforts, we have found that processing parameters required to fabricate high-efficiency substrate CdTe PV devices differ from those necessary for traditional superstrate CdTe devices. Here, we investigate how oxygen incorporation in the CdTe deposition, CdCl2 heat treatment, CdS deposition, and post-deposition heat treatment affect device characteristics through their effects on the junction. By adjusting whether oxygen is incorporated during these processing steps, we have achieved Voc values greater than 860 mV and efficiencies greater than 10%.
Duenow, J. N.; Dhere, R. G.; Kuciauskas, D.; Li, J. V.; Pankow, J. W.; DeHart, C. M.; Gessert, T. A.
Defect Levels of Indium-doped CdMnTe Crystals
Science Conference Proceedings (OSTI)
Using photoluminescence (PL) and current deep-level transient spectroscopy (I-DLTS), we investigated the electronic defects of indium-doped detector-grade CdMnTe:In (CMT:In) crystals grown by the vertical Bridgman method. We similarly analyzed CdZnTe:In (CZT:In) and undoped CdMnTe (CMT) crystals grown under the amount of same level of excess Te and/or indium doping level to detail the fundamental properties of the electronic defect structure more readily. Extended defects, existing in all the samples, were revealed by synchrotron white beam x-ray diffraction topography and scanning electron microscopy. The electronic structure of CMT is very similar to that of CZT, with shallow traps, A-centers, Cd vacancies, deep levels, and Te antisites. The 1.1-eV deep level, revealed by PL in earlier studies of CZT and CdTe, were attributed to dislocation-induced defects. In our I-DLTS measurements, the 1.1-eV traps showed different activation energies with applied bias voltage and an exponential dependence on the trap-filling time, which are typical characteristics of dislocation-induced defects. We propose a new defect-trap model for indium-doped CMT crystals.
K Kim; A Bolotinikov; G Camarda; R Gul; A Hossain; G Yang; Y Cui; R James
Valence Band Structure of Highly Efficient p-type Thermoelectric PbTe-PbS Alloys
Science Conference Proceedings (OSTI)
New experimental evidence is given relevant to the temperature-dependence of valence band structure of PbTe and PbTe1-xSx alloys (0.04 x 0.12), and its effect on the thermoelectric figure of merit zT. The x = 0.08 sample has zT ~ 1.55 at 773K. The magnetic field dependence of the high-temperature Hall resistivity of heavily p-type (> 1019 cm-3) Na-doped PbTe1-xSx reveals the presence of high-mobility electrons. This put in question prior analyses of the Hall coefficient and the conclusion that PbTe would be an indirect gap semiconductor at temperatures where its zT is optimal. Possible origins for these electrons are discussed: they can be induced by photoconductivity, or by the topology of the Fermi surface when the L and -bands merge. Negative values for the low-temperature thermopower are also observed. Our data show that PbTe continues to be a direct gap semiconductor at temperatures where the zT and S2 of p-type PbTe are optimal e.g. 700-900K. The previously suggested temperature induced rapid rise in energy of the heavy hole LVB relative to the light hole UVB is not supported by the experimental data.
Jaworski, C. M. [Ohio State University; Nielsen, Mechele [Ohio State University; Wang, Hsin [ORNL; Girard, Steven N. [Northwestern University, Evanston; Cai, Wei [ORNL; Porter, Wallace D [ORNL; Kanatzidis, Mercouri G. [Northwestern University, Evanston; Heremans, J. P. [Ohio State University
Can TeVeS avoid Dark Matter on galactic scales?
A fully relativistic analysis of gravitational lensing in TeVeS is presented. By estimating the lensing masses for a set of six lenses from the CASTLES database, and then comparing them to the stellar mass, the deficit between the two is obtained and analysed. Considering a parametrised range for the TeVeS function $mu(y)$, which controls the strength of the modification to gravity, it is found that on galactic scales TeVeS requires additional dark matter with the commonly used $mu(y)$. A soft dependence of the results on the cosmological framework and the TeVeS free parameters is discussed. For one particular form of $mu(y)$, TeVeS is found to require very little dark matter. This choice is however ruled out by rotation curve data. The inability to simultaneously fit lensing and rotation curves for a single form of $mu(y)$ is a challenge to a "no dark matter" TeVeS proposal.
Nick E. Mavromatos; Mairi Sakellariadou; Muhammad Furqaan Yusaf
DEVELOPMENT OF CdZnTe RADIATION DETECTORS
Science Conference Proceedings (OSTI)
Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for room-temperature semiconductor detectors because of its wide band-gap and high atomic number. Despite these advantages, CZT still presents some material limitations and poor hole mobility. In the past decade most of the developing CZT detectors focused on designing different electrode configurations, mainly to minimize the deleterious effect due to the poor hole mobility. A few different electrode geometries were designed and fabricated, such as pixelated anodes and Frisch-grid detectors developed at Brookhaven National Lab (BNL). However, crystal defects in CZT materials still limit the yield of detector-grade crystals, and, in general, dominate the detector's performance. In the past few years, our group's research extended to characterizing the CZT materials at the micro-scale, and to correlating crystal defects with the detector's performance. We built a set of unique tools for this purpose, including infrared (IR) transmission microscopy, X-ray micro-scale mapping using synchrotron light source, X-ray transmission- and reflection-topography, current deep level transient spectroscopy (I-DLTS), and photoluminescence measurements. Our most recent work on CZT detectors was directed towards detailing various crystal defects, studying the internal electrical field, and delineating the effects of thermal annealing on improving the material properties. In this paper, we report our most recent results.
Science Conference Proceedings (OSTI)
The major problem of measurement of a power spectral density (PSD) distribution of the surface heights with surface profilometers arises due to the unknown Modulation Transfer Function (MTF) of the instruments. The MTF tends to distort the PSD at higher spatial frequencies. It has been suggested [Proc. SPIE 7077-7, (2007), Opt. Eng. 47 (7), 073602-1-5 (2008)] that the instrumental MTF of a surface profiler can be precisely measured using standard test surfaces based on binary pseudo-random (BPR) patterns. In the cited work, a one dimensional (1D) realization of the suggested method based on use of BPR gratings has been demonstrated. Here, we present recent achievements made in fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. The 2D BPRAs were used as standard test surfaces for 2D MTF calibration of the MicromapTM-570 interferometric microscope with all available objectives. The effects of fabrication imperfections on the efficiency of calibration are also discussed.
Barber, Samuel K.; Soldate, Paul; Anderson, Erik H.; Cambie, Rossana; Marchesini, Stefano; McKinney, Wanye R.; Takacs, Peter Z.; Voronov, Dmitry L.; Yashchuk, Valeriy V.
High quality Bi2Te3 and Sb2Te3 topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy. Their growth and behavior on both vicinal and non-vicinal GaAs (111) substrates were investigated by reflection high-energy electron diffraction, atomic force microscopy, x-ray diffraction, and high resolution transmission electron microscopy. It is found that non-vicinal GaAs (111) substrate is better than a vicinal substrate to provide high quality Bi2Te3 and Sb2Te3 films. Hall and magnetoresistance measurements indicate that p type Sb2Te3 and n type Bi2Te3 topological insulator films can be directly grown on a GaAs (111) substrate, which may pave a way to fabricate topological insulator p-n junction on the same substrate, compatible with the fabrication process of present semiconductor optoelectronic devices.
Zhaoquan Zeng; Timothy A. Morgan; Dongsheng Fan; Chen Li; Yusuke Hirono; Xian Hu; Yanfei Zhao; Joon Sue Lee; Zhiming M. Wang; Jian Wang; Shuiqing Yu; Michael E. Hawkridge; Mourad Benamara; Gregory J. Salamo
Development of a Total Energy, Environment and Asset Management (TE2AM tm) Curriculum
Science Conference Proceedings (OSTI)
The University of Wisconsin Department of Engineering Professional Development (EPD) has completed the sponsored project entitled, Development of a Total Energy, Environment and Asset Management (TE2AM�) Curriculum. The project involved the development of a structured professional development program to improve the knowledge, skills, capabilities, and competencies of engineers and operators of commercial buildings. TE2AM� advances a radically different approach to commercial building design, operation, maintenance, and end-�?of-�?life disposition. By employing asset management principles to the lifecycle of a commercial building, owners and occupants will realize improved building performance, reduced energy consumption and positive environmental impacts. Through our commercialization plan, we intend to offer TE2AM� courses and certificates to the professional community and continuously improve TE2AM� course materials. The TE2AM� project supports the DOE Strategic Theme 1 -�? Energy Security; and will further advance the DOE Strategic Goal 1.4 Energy Productivity. Through participation in the TE2AM� curriculum, engineers and operators of commercial buildings will be eligible for a professional certificate; denoting the completion of a prescribed series of learning activities. The project involved a comprehensive, rigorous approach to curriculum development, and accomplished the following goals: 1. Identify, analyze and prioritize key learning needs of engineers, architects and technical professionals as operators of commercial buildings. 2. Design and develop TE2AM� curricula and instructional strategies to meet learning needs of the target learning community. 3. Establish partnerships with the sponsor and key stakeholders to enhance the development and delivery of learning programs. 4. Successfully commercialize and sustain the training and certificate programs for a substantial time following the term of the award. The project team was successful in achieving the goals and deliverables set forth in the original proposal. Though attempts were made to adhere to the original project timeline, the team requested, and was granted a 6-�?month project extension, during which time the project was completed.
A Search for a Light Charged Higgs Boson Decaying to cs at ?s = 7 TeV.
??A search for a light charged Higgs boson decaying into cs is presented using data recorded in pp collisions at ?s = 7 TeV. The� (more)
Martyniuk, Alex Christopher
This presentation outlines an analysis of alternate methods to obtain stabilized power performance of CdTe and CIGS PV modules.
del Cueto, J. A.; Deline, C. A.; Rummel, S.
Exploring alternative symmetry breaking mechanisms at the LHC with 7, 8 and 10 TeV total energy
In view of the annnouncement that in 2012 the LHC will run at 8 TeV, we study the possibility of detecting signals of alternative mechanisms of ElectroWeak Symmetry Breaking, described phenomenologically by unitarized models, at energies lower than 14 TeV. A complete calculation with six fermions in the final state is performed using the PHANTOM event generator. Our results indicate that at 8 TeV some of the scenarios with TeV scale resonances are likely to be identified while models with no resonances or with very heavy ones will be inaccessible, unless the available luminosity will be much higher than expected.
Alessandro Ballestrero; Diogo Buarque Franzosi; Ezio Maina
Damage Detection of CFRP Plates by Full-Spectral Analysis of a Fibre Bragg Grating Sensor Signal
Science Conference Proceedings (OSTI)
This paper describes the measurement of average strain, strain distribution and vibration of cantilever beam made of Carbon Fiber Reinforced Plastics (CFRP), using a single Fibre Bragg Grating (FBG) sensor mounted on the beam surface. Average strain is determined from the displacement of the peak wavelength of reflected light from the FBG sensor. Unstrained reference FBG sensors were used to compensate for temperature drift and the photoelastic coefficient (P{sub e}), which was used to calculate the gauge factor. Measured strains agree with those measured by a resistance foil strain gauge attached to the sample. Stress distributions are measured by monitoring the variation in the full width half maximum (FWHM) values of the reflected spectrum, using a proposed optical analytical model, described in the paper. FWHM values were measured for both the cantilever test beam and a for a reference beam, loaded using a four-point bending rig. The trend of the stress distribution for the test beam matches with our analytical model, however with a relatively large noise present in the experimentally determined data. The vibration of cantilever beam was measured by temporal analysis of the peak reflection wavelength. This technique is very stable as measurements are not affected by variations in the signal amplitude. Finally an application of FBG sensors for damage detection of CFRP plates is demonstrated, by measuring the average strain and natural frequency. With small defects of different sizes applied to the CFRP plate, average strains were seen to increase with damage size and the natural frequency decreased with damage size.
Mizutani, Yoshihiro [Optical Non-Destructive Testing Laboratory, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2600 GB Delft (Netherlands); Solid and Structures Engineering Laboratory, Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, Japan, 2-12-1-I1-70, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Groves, Roger M. [Optical Non-Destructive Testing Laboratory, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2600 GB Delft (Netherlands)
Science Conference Proceedings (OSTI)
Spectrometer-grade CdTe single crystals with resistivities higher than 10{sup 9} {Omega} cm have been grown by the modified Bridgman method using zone-refined precursor materials (Cd and Te) under a Cd overpressure. The grown CdTe crystals had good charge-transport properties ({mu}{tau}{sub e} = 2 x 10{sup -3} cm{sup 2} V{sup -1}, {mu}{tau}{sub h} = 8 x 10{sup -5} cm{sup 2} V{sup -1}) and significantly reduced Te precipitates compared with crystals grown without Cd overpressure. The crystal growth conditions for the Bridgman system were optimized by computer modeling and simulation, using modified MASTRAPP program, and applied to crystal diameters of 14 mm (0.55'), 38 mm (1.5'), and 76 mm (3'). Details of the CdTe crystal growth operation, structural, electrical, and optical characterization measurements, detector fabrication, and testing using {sup 241}Am (60 keV) and {sup 137}Cs (662 keV) sources are presented.
Mandal, Krishna [EIC Laboratories, Inc.; Kang, Sung Hoon [EIC Laboratories, Inc.; Choi, Michael [EIC Laboratories, Inc.; Wei, Jiuan [State University of New York, Stony Brook; Zheng, Lili [State University of New York, Stony Brook; Zhang, Hui [State University of New York, Stony Brook; Jellison Jr, Gerald Earle [ORNL; Groza, Michael [Fisk University, Nashville, TN; Burger, Arnold [Fisk University, Nashville, TN
An orthogonal full-factorial design was used to study the effect of CdS and CdTe layer thickness, oxygen ambient during vapor CdCl2 (VCC) and the use of nitric-phosphoric (NP) acid as a pre-contact etch on the initial and stressed performance of CdS/CdTe small-area devices. The best initial device efficiency (using thinner CdS, thicker CdTe, no oxygen during VCC, and NP etch) also showed poor stability. Increasing the CdS thickness significantly improved stability with only a slight decrease in resulting initial performance. All devices used a thin margin of CdTe around the perimeter of the backcontact that was shown to significantly reduce catastrophic degradation and improve overall test statistics. The latter degradation is modeled by the formation of a weak-diode/low shunt resistance localized near the edge of finished devices. This shunting is believed to occur through the CdS/CdTe interface, rather than along the device edge, and is exacerbated by thinner CdS films.
Albin, D.; McMahon, T.; Berniard, T.; Pankow, J.; Demtsu, S.; Noufi, R.
An Experiment to Locate the Site of TeV Flaring in M87
We describe a Chandra X-ray target-of-opportunity project designed to isolate the site of TeV flaring in the radio galaxy M87. To date, we have triggered the Chandra observations only once (2010 April) and by the time of the first of our nine observations, the TeV flare had ended. However, we found that the X-ray intensity of the unresolved nucleus was at an elevated level for our first observation. Of the more than 60 Chandra observations we have made of the M87 jet covering nine years, the nucleus was measured at a comparably high level only three times. Two of these occasions can be associated with TeV flaring, and at the time of the third event, there were no TeV monitoring activities. From the rapidity of the intensity drop of the nucleus, we infer that the size of the emitting region is of order a few light days x the unknown beaming factor; comparable to the same sort of estimate for the TeV emitting region. We also find evidence of spectral evolution in the X-ray band which seems consistent with radiative losses affecting the non-thermal population of the emitting electrons within the unresolved nucleus.
Harris, D.E.; /Harvard-Smithsonian Ctr. Astrophys.; Massaro, F.; /Harvard-Smithsonian Ctr. Astrophys. /KIPAC, Menlo Park /SLAC; Cheung, C.C.; /Natl. Acad. Sci. /Naval Research Lab, Wash., D.C.; Horns, D.; Raue, M.; /Hamburg U.; Stawarz, L.; /JAXA, Sagamihara /Jagiellonian U., Astron. Observ.; Wagner, S.; /Heidelberg Observ.; Colin, P.; /Munich, Max Planck Inst.; Mazin, D.; /Barcelona, IFAE; Wagner, R.; /Munich, Max Planck Inst.; Beilicke, M.; /McDonnell Ctr. Space Sci.; LeBohec, S.; Hui, M.; /Utah U.; Mukherjee, R.; /Barnard Coll.
A Search for TeV Gamma-Ray Burst Emission with the Milagro Observatory
The Milagro telescope monitors the northern sky for 100 GeV - 100 TeV transient emission through continuous very high energy wide-field observations. The large effective area and low energy threshold of Milagro allow it to detect very high energy gamma-ray burst emission with much higher sensitivity than previous instruments, and a fluence sensitivity at TeV energies comparable to dedicated gamma-ray burst satellites at keV-MeV energies. Observation of gamma-ray burst emission at TeV energies could place important constraints on gamma-ray burst progenitor and emission models. This study details the development of a weighted analysis technique; the implementation of this technique to perform a real time search for TeV transients of 40 seconds to 3 hours duration in the Milagro data; and the results from more than one year of observation. Between May 2nd, 2001, and May 22nd, 2002, no TeV transients of 40 seconds to 3 hours duration were observed. Upper limits on both observed and emitted high energy gamma-ray burst emission are presented.
Miguel F. Morales
Investigation of the Charge Collection Efficiency of CdMnTe Radiation Detectors
This paper presents the growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe) crystals grown by the vertical Bridgman technique. The 10 x 10 x 1.9 mm{sup 3} samples have been fabricated, and the charge collection properties of the CdMnTe detectors have been measured. Alpha-particle spectroscopy measurements have yielded an average charge collection efficiency approaching 100%. Ion beam induced charge (IBIC) measurements have been performed by raster scanning focused 5.5 MeV {sup 4}He beams onto the detectors. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of Te inclusions within the detector bulk, and the reduction in charge collection efficiency in their locality has been quantified. It has been shown that the role of Te inclusions in degrading charge collection is reduced with increasing values of bias voltage. IBIC measurements for a range of low biases have highlighted the evolution of the charge collection uniformity across the detectors.
Bolotnikov A.; Rafiei, R.; Boardman, D.; Sarbutt, A.; Prokopovich, A.; Kim, K.; Reinhard, M.I.; James, R.B.
Hybrid model of GeV-TeV gamma ray emission from Galactic Center
The observations of high energy $\\gamma$-ray emission from the Galactic center (GC) by HESS, and recently by Fermi, suggest the cosmic ray acceleration in the GC and possibly around the supermassive black hole. In this work we propose a lepton-hadron hybrid model to explain simultaneously the GeV-TeV $\\gamma$-ray emission. Both electrons and hadronic cosmic rays were accelerated during the past activity of the GC. Then these particles would diffuse outwards and interact with the interstellar gas and background radiation field. The collisions between hadronic cosmic rays with gas is responsible to the TeV $\\gamma$-ray emission detected by HESS. With fast cooling in the strong radiation field, the electrons would cool down and radiate GeV photons through inverse Compton scattering off the soft background photons. This scenario provides a natural explanation of the observed GeV-TeV spectral shape of $\\gamma$-rays.
Yi-Qing Guo; Qiang Yuan; Cheng Liu; Ai-Feng Li
Experimental study of double-{beta} decay modes using a CdZnTe detector array
An array of sixteen 1 cm{sup 3} CdZnTe semiconductor detectors was operated at the Gran Sasso Underground Laboratory (LNGS) to further investigate the feasibility of double-{beta} decay searches with such devices. As one of the double-{beta} decay experiments with the highest granularity the 4x4 array accumulated an overall exposure of 18 kg days. The setup and performance of the array is described. Half-life limits for various double-{beta} decay modes of Cd, Zn, and Te isotopes are obtained. No signal has been found, but several limits beyond 10{sup 20} years have been performed. They are an order of magnitude better than those obtained with this technology before and comparable to most other experimental approaches for the isotopes under investigation. An improved limit for the {beta}{sup +}/EC decay of {sup 120}Te is given.
Dawson, J. V. [Laboratoire Astroparticule et Cosmologie, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris (France); Goessling, C.; Koettig, T.; Muenstermann, D.; Rajek, S.; Schulz, O. [Lehrstuhl fuer Experimentelle Physik IV, Technische Universitaet Dortmund, Otto-Hahn Str. 4, D-44227 Dortmund (Germany); Janutta, B.; Zuber, K. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, D-01069 Dresden (Germany); Junker, M. [Laboratori Nazionali del Gran Sasso, Assergi (Italy); Reeve, C. [University of Sussex, Falmer, Brighton BN1 9QH (United Kingdom); Wilson, J. R. [University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)
Experimental Realization of a Three-Dimensional Topological Insulator, Bi 2Te3
Three-dimensional topological insulators are a new state of quantum matter with a bulk gap and odd number of relativistic Dirac fermions on the surface. By investigating the surface state of Bi{sub 2}Te{sub 3} with angle-resolved photoemission spectroscopy, we demonstrate that the surface state consists of a single nondegenerate Dirac cone. Furthermore, with appropriate hole doping, the Fermi level can be tuned to intersect only the surface states, indicating a full energy gap for the bulk states. Our results establish that Bi{sub 2}Te{sub 3} is a simple model system for the three-dimensional topological insulator with a single Dirac cone on the surface. The large bulk gap of Bi{sub 2}Te{sub 3} also points to promising potential for high-temperature spintronics applications.
Siemons, W.
Energy spectrum of charge carriers in Ag{sub 2}Te
Science Conference Proceedings (OSTI)
On the basis of investigations of the temperature and concentration dependences of kinetic coefficients (the Hall coefficientR, the electrical conductivity {sigma}, and thermopower {alpha}{sub 0}) in n-type Ag{sub 2}Te, it is established that Ag atoms in Ag{sub 2}Te create the shallow donor levels located at a distance of (0.002-7 x 10{sup -5}T) eV from the bottom of the conduction band. It is shown that silver telluride has n-type conductivity starting with the deficiency of Ag {>=} 0.01 at % in the stoichiometric composition, and it is practically impossible to achieve the stoichiometric composition in Ag{sub 2}Te.
Aliev, F. F., E-mail: email@example.com; Jafarov, M. B. [Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)
Z' Bosons, the NuTeV Anomaly, and the Higgs Boson Mass
Fits to the precision electroweak data that include the NuTeV measurement are considered in family universal, anomaly free U(1) extensions of the Standard Model. In data sets from which the hadronic asymmetries are excluded, some of the Z{prime} models can double the predicted value of the Higgs boson mass, from {approx} 60 to {approx} 120 GeV, removing the tension with the LEP II lower bound, while also modestly improving the {chi}{sup 2} confidence level. The effect of the Z{prime} models on both m{sub H} and the {chi}{sup 2} confidence level is increased when the NuTeV measurement is included in the fit. Both the original NuTeV data and a revised estimate by the PDG are considered.
Chanowitz, Michael S
Spiral growth of topological insulator Sb{sub 2}Te{sub 3} nanoplates
Sb{sub 2}Te{sub 3} nanoplates synthesized by vapor phase deposition method have been systemically investigated employing atomic force microscopy, which exhibit regular spiral structures on the surface. The height of spiral steps is determined to be 1 nm corresponding to one quintuple layer, with an inter-step separation ranging from 500 nm to 1 {mu}m. Growth mechanism of spiral structures on the Sb{sub 2}Te{sub 3} nanoplate surface is elucidated, which can be applied to other layered materials with van der Waals epitaxy growth. The electrostatic properties of Sb{sub 2}Te{sub 3} nanoplates with spiral structures are also simultaneously characterized.
Hao Guolin; Qi Xiang; Fan Yinping; Xue Lin; Peng Xiangyang; Wei Xiaolin; Zhong Jianxin [Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105 (China) and Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan 411105 (China)] [Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Xiangtan University, Hunan 411105 (China) and Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan 411105 (China)
Dark Current Transients in Thin-Film CdTe Solar Cells: Preprint
This conference paper describes the Dark current transients measured by changing the voltage bias in a stepwise fashion on CdTe cells results in minutes-long transients after each step. Transients measured at room temperature are controlled by carrier trapping that corresponds to the well known voltage transient phenomena[1]. Transients measured on the same CdTe cell at elevated temperature (60C and 90C) show a much slower decay process. We associate this physical process with''shunt'' current paths induced with reverse bias and removed with forward bias. A different back contact process may produce an opposite voltage dependence. The lack of these transients may be required for the fabrication of ''stable'' thin-film CdTe solar cells.
McMahon, T. J.
Advances in the In-House CdTe Research Activities at NREL
NREL in-house CdTe research activities have impacted a broad range of recent program priorities. Studies aimed at industrially relevant applications have produced new materials and processes that enhance the performance of devices based on commercial materials (e.g., soda-lime glass, SnO2:F). Preliminary tests of the effectiveness of these novel components using large-scale processes have been encouraging. Similarly, electro- and nano-probe techniques have been developed and used to study the evolution and function of CdTe grain boundaries. Finally, cathodoluminescence (CL) and photoluminescence (PL) studies on single-crystal samples have yielded improved understanding of how various processes may combine to produce important defects in CdTe films.
Gessert, T.; Wu, X.; Dhere, R.; Moutinho, H.; Smith, S.; Romero, M.; Zhou, J.; Duda, A.; Corwine, C.
Abidjan, Côte d'Ivoire: Energy Resources | Open Energy Information
Abidjan, Côte d'Ivoire: Energy Resources Abidjan, Côte d'Ivoire: Energy Resources Jump to: navigation, search Name Abidjan, Côte d'Ivoire Equivalent URI DBpedia GeoNames ID 2293538 Coordinates 5.341111°, -4.028056° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":5.341111,"lon":-4.028056,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Suzanne G.E. te Velthuis - Argonne National Laboratories, Materials Sicence
NLE Websites -- All DOE Office Websites (Extended Search)
The new lanthanum copper telluride La{sub 3}Cu{sub 5-x}Te{sub 7} has been obtained by annealing the elements at 1073 K. Single-crystal X-ray diffraction studies revealed that the title compound crystallizes in a new structure type, space group Pnma (no. 62) with lattice dimensions of a=8.2326(3) A, b=25.9466(9) A, c=7.3402(3) A, V=1567.9(1) A{sup 3}, Z=4 for La{sub 3}Cu{sub 4.86(4)}Te{sub 7}. The structure of La{sub 3}Cu{sub 5-x}Te{sub 7} is remarkably complex. The Cu and Te atoms build up a three-dimensional covalent network. The coordination polyhedra include trigonal LaTe{sub 6} prisms, capped trigonal LaTe{sub 7} prisms, CuTe{sub 4} tetrahedra, and CuTe{sub 3} pyramids. All Cu sites exhibit deficiencies of various extents. Electrical property measurements on a sintered pellet of La{sub 3}Cu{sub 4.86}Te{sub 7} indicate that it is a p-type semiconductor in accordance with the electronic structure calculations. -- Graphical abstract: Oligomeric unit comprising interconnected CuTe{sub 3} pyramids and CuTe{sub 4} tetrahedra. Display Omitted Research highlights: {yields} La{sub 3}Cu{sub 5-x}Te{sub 7} adopts a new structure type. {yields} All Cu sites exhibit deficiencies of various extents. {yields} The coordination polyhedra include trigonal LaTe{sub 6} prisms, capped trigonal LaTe{sub 7} prisms, CuTe{sub 4} tetrahedra and CuTe{sub 3} pyramids. {yields} La{sub 3}Cu{sub 5-x}Te{sub 7} is a p-type semiconductor.
Zelinska, Mariya; Assoud, Abdeljalil [Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada); Kleinke, Holger, E-mail: firstname.lastname@example.com [Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1 (Canada)
Based on the mechanism of incoherent diffraction radiation excited by an electron bunch in a waveguide with periodic structure, this paper presents the concept of coherent terahertz (THz) radiation from the high-harmonic component of a modulated free-electron beam in a tapered two-asymmetric grating structure. The results show that in this mechanism 0.43 THz radiation can be generated with 10 A/cm{sup 2} current density, and the efficiency can reach 0.5%. Because of the low required current density and relative high efficiency, this concept shows the application potential for electron-beam-driven terahertz sources.
Zhang Yaxin; Zhou Yucong; Dong Liang; Liu Shenggang [Terahertz Science and Technology Research Center, University of Electronic Science and Technology of China, Chengdu 610054 (China)
Science Conference Proceedings (OSTI)
The design and commissioning of a new soft X-ray beamline, BL-16A, at the Photon Factory is presented. The beamline consists of a pre-focusing mirror, an entrance slit, a variable-included-angle varied-line-spacing plane grating monochromator, and a post-focusing system as usual, and provides circularly and linearly polarized soft X rays in the energy range 200-1500 eV with an APPLE-II type undulator. The commissioning procedure for the beamline optics is described in detail, especially the check of the focal position for the zero-th order and diffracted X rays.
Amemiya, Kenta; Toyoshima, Akio; Kikuchi, Takashi; Kosuge, Takashi; Nigorikawa, Kazuyuki; Sumii, Ryohei; Ito, Kenji [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)
ZnTe:O phosphor development for x-ray imaging applications
Science Conference Proceedings (OSTI)
An efficient ZnTe:O x-ray powder phosphor was prepared by a dry synthesis process using gaseous doping and etching medias. The x-ray luminescent properties were evaluated and compared to standard commercial phosphors exhibited an x-ray luminescent efficiency equivalent to 76% of Gd{sub 2}O{sub 2}S:Tb and an equal resolution of 2.5 lines/mm. In addition, the fast decay time, low afterglow, and superior spectral match to conventional charge-coupled devices-indicate that ZnTe:O is a very promising phosphor candidate for x-ray imaging applications.
Kang, Z.T.; Summers, C.J.; Menkara, H.; Wagner, B.K.; Durst, R.; Diawara, Y.; Mednikova, G.; Thorson, T. [Phosphor Technology Center of Excellence, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia 30332-0826 (United States); Bruker AXS 5465 East Cheryl Parkway, Madison Wisconson 53711 (United States)
Ultrahigh Energy Cosmic Rays and Prompt TeV Gamma Rays from Gamma Ray Bursts
Gamma Ray Bursts (GRBs) have been proposed as one {\\it possible} class of sources of the Ultrahigh Energy Cosmic Ray (UHECR) events observed up to energies $\\gsim10^{20}\\ev$. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up to TeV energies. Here we briefly discuss the implications on the energetics of the GRB from the point of view of the detectability of the prompt TeV gamma rays of proton-synchrotron origin in GRBs in the up-coming ICECUBE muon detector in the south pole.
Pijushpani Bhattacharjee; Nayantara Gupta
High efficiency thin film CdTe and a-Si based solar cells
This report describes work done by the University of Toledo during the first year of this subcontract. During this time, the CdTe group constructed a second dual magnetron sputter deposition facility; optimized reactive sputtering for ZnTe:N films to achieve 10 ohm-cm resistivity and {approximately}9% efficiency cells with a copper-free ZnTe:N/Ni contact; identified Cu-related photoluminescence features and studied their correlation with cell performance including their dependence on temperature and E-fields; studied band-tail absorption in CdS{sub x}Te{sub 1{minus}x} films at 10 K and 300 K; collaborated with the National CdTe PV Team on (1) studies of high-resistivity tin oxide (HRT) layers from ITN Energy Systems, (2) fabrication of cells on the HRT layers with 0, 300, and 800-nm CdS, and (3) preparation of ZnTe:N-based contacts on First Solar materials for stress testing; and collaborated with Brooklyn College for ellipsometry studies of CdS{sub x}Te{sub 1{minus}x} alloy films, and with the University of Buffalo/Brookhaven NSLS for synchrotron X-ray fluorescence studies of interdiffusion in CdS/CdTe bilayers. The a-Si group established a baseline for fabricating a-Si-based solar cells with single, tandem, and triple-junction structures; fabricated a-Si/a-SiGe/a-SiGe triple-junction solar cells with an initial efficiency of 9.7% during the second quarter, and 10.6% during the fourth quarter (after 1166 hours of light-soaking under 1-sun light intensity at 50 C, the 10.6% solar cells stabilized at about 9%); fabricated wide-bandgap a-Si top cells, the highest Voc achieved for the single-junction top cell was 1.02 V, and top cells with high FF (up to 74%) were fabricated routinely; fabricated high-quality narrow-bandgap a-SiGe solar cells with 8.3% efficiency; found that bandgap-graded buffer layers improve the performance (Voc and FF) of the narrow-bandgap a-SiGe bottom cells; and found that a small amount of oxygen partial pressure ({approximately}2 {times} 10{sup {minus}5} torr) was beneficial for growing high-quality films from ITO targets.
Compaan, A. D.; Deng, X.; Bohn, R. G.
An updated search for heavy narrow resonances decaying to muon or electron pairs using the CMS detector is presented. Data samples from pp collisions at $\\sqrt{s}$ = 7 TeV and 8 TeV at the LHC, with integrated luminosities of up to 5.3 and 4.1 inverse femtobarns, respectively, are combined. No evidence for a heavy narrow resonance is observed. The analysis of the combined data sets excludes, at 95% confidence level, a Sequential Standard Model Z'$_{SSM}$ resonance lighter than 2590 GeV, a superstring-inspired Z'$_{\\psi}$ lighter than 2260 GeV, and Kaluza-Klein gravitons lighter than 2390 (2030) GeV, assuming that the coupling parameter $k/\\bar{M}_{Pl}$ is 0.10 (0.05). These are the most stringent limits to date.
Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Er�, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; H�rmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Kn�nz, Valentin; Krammer, Manfred; Kr�tschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Sch�fbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; L�onard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Reis, Thomas; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, J�r�mie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Sigamani, Michael; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Ald� J�nior, Walter Luiz; Carvalho, Wagner; Cust�dio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Malek, Magdalena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Vilela Pereira, Antonio; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Carrillo Montoya, Camilo Andres; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Morovic, Srecko; Tikvica, Lucija; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Kuotb Awad, Alaa Metwaly; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; M�ntel, Mait; Murumaa, Marion; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; H�rk�nen, Jaakko; Heikkinen, Mika Aatos; Karim�ki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lamp�n, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lind�n, Tomas; Luukka, Panja-Riina; M�enp��, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Korpela, Arja; Tuuva, Tuure
Search for heavy narrow dilepton resonances in pp collisions at sqrt(s) = 7 TeV and sqrt(s) = 8 TeV
An updated search for heavy narrow resonances decaying to muon or electron pairs using the CMS detector is presented. Data samples from pp collisions at sqrt(s) = 7 TeV and 8 TeV at the LHC, with integrated luminosities of up to 5.3 and 4.1 inverse femtobarns, respectively, are combined. No evidence for a heavy narrow resonance is observed. The analysis of the combined data sets excludes, at 95% confidence level, a Sequential Standard Model Z'[SSM] resonance lighter than 2590 GeV, a superstring-inspired Z'[psi] lighter than 2260 GeV, and Kaluza-Klein gravitons lighter than 2390 (2030) GeV, assuming that the coupling parameter k/M-bar[Pl] is 0.10 (0.05). These are the most stringent limits to date.
CMS Collaboration
Science Conference Proceedings (OSTI)
Adhesion of pattern structures is a very important issue in laser thermal lithography. In this paper, Si"3N"4 and ZnS-SiO"2 were investigated as interface layers to improve patterns' adhesion to substrate on pattern fabrication with Ge"2Sb"2Te"5 as laser ... Keywords: Adhesion, GeSbTe, Interface layers, Thermal lithography, Thin films, Wet etching
Changmeng Deng; Yongyou Geng; Yiqun Wu; Yang Wang; Jinsong Wei
Advances in large-area Hg1-xCdxTe photovoltaic detectors for remote-sensing applications
Science Conference Proceedings (OSTI)
State-of-the-art large-area photovoltaic (PV) detectors fabricated in HgCdTe grown by molecular beam epitaxy (MBE) have been demonstrated for the Crosstrack Infrared Sounder (CrIS) instrument. Large-area devices (1 mm in diameter) yielded excellent electrical ... Keywords: HgCdTe, crosstrack infrared sounder, molecular beam epitaxy (MBE), photovoltaic detectors, remote sensing
P. S. Wijewarnasuriya; M. Zandian; J. Phillips; D. Edwall; R. E. Dewames; G. Hildebrandt; J. Bajaj; J. M. Arias; A. I. D'Souza; F. Moore
Science Conference Proceedings (OSTI)
Nano imprinting technology and the electrodeposition method were applied to make CdTe nano patterns on flexible substrates. An ammonia based aqueous solution was prepared at pH 10.7 and indium tin oxide (ITO)/polyethylene naphthalate (PEN) film with ... Keywords: CdTe nano pattern, Electrodeposition, Flexible substrate, Nano imprinting
Seungju Chun; Kang-Soo Han; Ju-Hyeon Shin; Heon Lee; Donghwan Kim
Science Conference Proceedings (OSTI)
Sb{sub 2}Te3 and Bi{sub 2}Te3 thin films were grown on SiO{sub 2} and BaF{sub 2} substrates at room temperature using molecular beam epitaxy. Metallic layers with thicknesses of 0.2 nm were alternately deposited at room temperature, and the films were subsequently annealed at 250 C for 2 h. x-Ray diffraction and energy-filtered transmission electron microscopy (TEM) combined with high-accuracy energy-dispersive x-ray spectrometry revealed stoichiometric films, grain sizes of less than 500 nm, and a texture. High-quality in-plane thermoelectric properties were obtained for Sb{sub 2}Te3 films at room temperature, i.e., low charge carrier density (2.6 x 10{sup 19} cm{sup -3}, large thermopower (130 {micro}V K{sup -1}), large charge carrier mobility (402 cm{sup 2} V{sup -1} s{sup -1}), and resulting large power factor (29 {micro}W cm{sup -1} K{sup -2}). Bi{sub 2}Te3 films also showed low charge carrier density (2.7 x 10{sup 19} cm{sup -3}), moderate thermopower (-153 {micro}V K{sup -1}), but very low charge carrier mobility (80 cm{sup 2} V{sup -1} s{sup -1}), yielding low power factor (8 {micro}W cm{sup -1} K{sup -2}). The low mobilities were attributed to Bi-rich grain boundary phases identified by analytical energy-filtered TEM.
Aabdin, Z.; Peranio, N.; Winkler, M.; Bessas, D.; K�nig, J.; Hermann, R.P.; B�ttner, H.; Eibl, O. (Julich); (Tubingen); (Fraunhofer)
The hot-wall vacuum evaporator system has been put into use with successful deposition of seven thin films of n-type CdTe on glass. Microprobe analysis indicated that the films were stoichiometric CdTe. Optical transmission showed a well-defined absorption edge. Film resistivities on glass were reduced from 1.7 x 10/sup 8/ ohm-cm, to 6 x 10/sup 4/ ohm-cm by In doping; film resistivities under AM1.5 illumination are 2.0 x 10/sup 4/ and 5 x 10/sup 2/ ohm-cm, respectively compared to the dark values given above. Temperature dependence of the dark conductivity of the undoped CdTe film indicates an activation energy of 0.79 eV; in the light the activation energy was reduced to 0.1 eV. The high dark resistivity and activation energy indicate high intergrain potential barriers, which could produce the high resistivities observed even with fairly high free electron densities in the grains. Comparison will be sought between these results and those found for films deposited epitaxially on single crystal substrates. A detailed summary of absorption constant vs wavelength data for CdTe has been assembled for both single crystal and thin film materials. The absorption constant for thin film material appears to vary from 2 x 10/sup 4/ cm/sup -1/ at 8000A to 10/sup 5/ cm/sup -1/ at 5000A; single crystal values may be slightly higher. EBIC and light scanning techniques are being developed for characterizing grain boundary effects in bicrystals, and to evaluate the effects of passivation techniques. Defect densities at a grain boundary in a p-type bicrystal were found to range from 2 x 10/sup 12/ to 8 x 10/sup 12/ cm/sup -2/eV/sup -1/, using data derived from the J-V dependence of the grain boundary.
Bube, R H
Science Conference Proceedings (OSTI)
The recently discovered three-dimensional topological insulator Bi{sub 2}Te{sub 3} is studied as function of pressure in terms of crystal structures, resistance, and Hall coefficient. The superconductivity is found in phase I (ambient phase) Bi{sub 2}Te{sub 3} with T{sub c}-3 K, which is related to the topological features. The evolution of crystal structure with pressure is investigated by high pressure synchrotron radiation experiments that reveal structural transitions occurring at about 8 GPa, 13 GPa, and 16 GPa, respectively. Furthermore, the high pressure phases of Bi{sub 2}Te{sub 3} are also superconducting but with much higher T{sub c}-8 K. The superconducting transitions are compared with those for Bi, Te elements. A global phase diagram of Bi{sub 2}Te{sub 3} as function of pressure up to 30 GPa is obtained.
Zhang, S.J.; Zhang, J.L.; Yu, X.H.; Zhu, J.; Kong, P.P.; Feng, S.M.; Liu, Q.Q.; Yang, L.X.; Wang, X.C.; Cao, L.Z.; Yang, W.G.; Wang, L.; Mao, H.K.; Zhao, Y.S.; Liu, H.Z.; Dai, X.; Fang, Z.; Zhang, S.C.; Jin, C.Q. (Stanford); (Harbin); (UST - China); (CIW); (Chinese Aca. Sci.); (LANL)
Coherent optical phonon spectroscopy studies of femtosecond-laser modified Sb{sub 2}Te{sub 3} films
Science Conference Proceedings (OSTI)
We performed time-resolved reflectivity measurements to monitor changes in optical phonon modes in Sb{sub 2}Te{sub 3} thin films under femtosecond laser irradiation. We found that a phonon mode at 3.64 THz appears after high-fluence laser irradiation, in addition to the phonon modes of Sb{sub 2}Te{sub 3}. We determined that the additional mode is due to Te segregation as a result of laser-induced decomposition of the Sb{sub 2}Te{sub 3} film. This experiment clearly illustrates the irreversible effects of femtosecond laser irradiation during the measurement of coherent optical phonon dynamics in Sb{sub 2}Te{sub 3}.
Li Yuwei; Wang Guoyu [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Center for Solar and Thermal Energy Conversion, University of Michigan, Michigan 48109 (United States); Stoica, Vladimir A. [Center for Solar and Thermal Energy Conversion, University of Michigan, Michigan 48109 (United States); Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Endicott, Lynn [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Uher, Ctirad; Clarke, Roy [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Center for Solar and Thermal Energy Conversion, University of Michigan, Michigan 48109 (United States); Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States)
We present the first grating-resolution X-ray spectra of the X-ray binary Cir X-1, obtained with the High Energy Transmission Grating Spectrometer on Chandra. These reveal a rich set of lines from H-like and/or He-like Ne, Mg, Si, S and Fe detected with a high signal-to-noise ratio. The lines are broad (+/- 2000 km/s) and show P Cygni profiles. The absorption components of the lines extend to low velocity, and they have about the same widths and strengths as the corresponding emission components. The widths of the X-ray P Cygni lines are comparable to that of the broad component of the strong, asymmetric H-alpha line from Cir X-1, suggesting that the two phenomena may be related. We discuss outflow models and propose that the P Cygni profiles may arise in the moderate temperature (5 x 10^6 K) region of the wind from an X-ray heated accretion disk. This basic picture strengthens the idea that the accretion disk in Cir X-1 is viewed in a relatively edge-on manner, and it suggests that Cir X-1 is the X-ray binary analog of a Broad Absorption Line quasar.
W. N. Brandt; N. S. Schulz
Overcoming degradation mechanisms in CdTe solar cells: First annual report, August 1998--August 1999
The authors have studied the importance of chemical processes for the stability of CdTe solar cells, in particular, diffusion in the ohmic contact/absorber junction regions. Both whole cells and test systems containing only the ohmic contact and the absorber are used. They found several experimental methods to be useable tools to follow the effects of impurity diffusion on the CdTe grain boundaries, grain bulk, and surface. In addition, they have explored alternative contacting schemes. The first year of activities led to the following tentative conclusions: Grain boundaries in CdTe/CdS cells are NOT fully passivated and are expected to be electrically active; There appears to be fast ionic diffusion in the vicinity of the Cu/HgTe/graphite back-contact, possibly enhanced by grain boundary diffusion; The macroscopic response to stress is different for cells with identical back-contact, but from different manufacturers. Different factors and/or different reactions to identical factors are possibly at work here; and Ni-P appears to be a promising back-contact material.
Cahen, D.; Gartsman, K.; Hodes, G.; Rotlevy, O.; Visoly-Fisher, I,; Dobson, K.
Results from a search for the 0 {nu}{beta}{beta}-decay of {sup 130}Te
A detailed description of the CUORICINO {sup 130}Te neutrinoless double-beta (0 {nu}{beta}{beta}) decay experiment is given and recent results are reported. CUORICINO is an array of 62 tellurium oxide (TeO{sub 2}) bolometers with an active mass of 40.7 kg. It is cooled to {approx}8-10 mK by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons. It is running in the Laboratori Nazionali del Gran Sasso (LNGS) in Assergi, Italy. These data represent an exposure of 11.83 kg yr or 91 mole-years of {sup 130}Te. No evidence for 0 {nu}{beta}{beta}-decay was observed and a limit of T{sub 1/2}{sup 0} {sup {nu}}({sup 130}Te){>=}3.0x10{sup 24} y (90% CL) is set. This corresponds to an upper limit on the effective mass,
Arnaboldi, C.; Brofferio, C.; Capelli, S.; Clemenza, M.; Fiorini, E.; Nucciotti, A.; Pavan, M.; Sisti, M. [Dipartimento di Fisica dell'Universita di Milano-Bicocca, I-20126 Milano (Italy); Sezione INFN di Milano-Bicocca, I-20126 Milano (Italy); Artusa, D. R.; Avignone III, F. T.; Bandac, I.; Creswick, R. J.; Farach, H. A.; Rosenfeld, C. [Department of Physics and Astronomy, University of South Carolina, Columbia, SC 29208 (United States); Balata, M.; Bucci, C.; Giachero, A.; Gorla, P.; Nisi, S. [INFN Laboratori Nazionali del Gran Sasso, I-67010, Assergi (L'Aquila) (Italy); Barucci, M. [Dipartimento di Fisica dell'Universita di Firenze, I-50019 Firenze (Italy); Sezione INFN di Firenze, I-50019, Firenze (Italy)] (and others)
Physical properties of Ce3-xTe4 below room temperature
Science Conference Proceedings (OSTI)
The physical properties of polycrystalline Ce{sub 3-x}Te{sub 4} were investigated by measurements of the thermoelectric properties, Hall coefficient, heat capacity, and magnetization. The fully filled, metallic x = 0 compound displays a soft ferromagnetic transition near 4 K, and analysis of the corresponding heat capacity anomaly suggests a doublet ground state for Ce{sup 3+}. The transition is suppressed to below 2 K in the insulating x = 0.33 composition, revealing that magnetic order in Ce{sub 3-x}Te{sub 4} is driven by a Ruderman-Kittel-Kasuya-Yosida (RKKY)-type interaction. The thermoelectric properties trend with composition as expected from simple electron counting, and the transport properties in Ce{sub 3}Te{sub 4} are observed to be similar to those in La{sub 3}Te{sub 4}. Trends in the low-temperature thermal conductivity data reveal that the phonons are efficiently scattered by electrons, while all compositions examined have a lattice thermal conductivity near 1.2 W/m K{sup -1} at 200 K.
May, Andrew F [ORNL; McGuire, Michael A [ORNL; Cantoni, Claudia [ORNL; Sales, Brian C [ORNL
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
solvents B-6 Pre-Combustion solvents u.s. DePartment of energy aDvanCeD Carbon DioxiDe CaPture r&D Program: teChnology uPDate, may 2013 Co 2 CaPture from igCC gas streams using...
Spray Deposition of High Quality CuInSe2 and CdTe Films: Preprint
A number of different ink and deposition approaches have been used for the deposition of CuInSe2 (CIS), Cu(In,Ga)Se2 (CIGS), and CdTe films. For CIS and CIGS, soluble precursors containing Cu, In, and Ga have been developed and used in two ways to produce CIS films. In the first, In-containing precursor films were sprayed on Mo-coated glass substrates and converted by rapid thermal processing (RTP) to In2Se3. Then a Cu-containing film was sprayed down on top of the In2Se3 and the stacked films were again thermally processed to give CIS. In the second approach, the Cu-, In-, and Ga-containing inks were combined in the proper ratio to produce a mixed Cu-In-Ga ink that was sprayed on substrates and thermally processed to give CIGS films directly. For CdTe deposition, ink consisting of CdTe nanoparticles dispersed in methanol was prepared and used to spray precursor films. Annealing these precursor films in the presence of CdCl2 produced large-grained CdTe films. The films were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Optimized spray and processing conditions are crucial to obtain dense, crystalline films.
Curtis, C. J.; van Hest, M.; Miedaner, A.; Leisch, J.; Hersh, P.; Nekuda, J.; Ginley, D. S.
Higgs Coupling Measurements at a 1 TeV Linear Collider
Methods for extracting Higgs boson signals at a 1 TeV center-of-mass energy e{sup +}e{sup -} linear collider are described. In addition, estimates are given for the accuracy with which branching fractions can be measured for Higgs boson decays to b{bar b} WW, gg, and {gamma}{gamma}.
Barklow, T
PyR@TE: Renormalization Group Equations for General Gauge Theories
Although the two-loop renormalization group equations for a general gauge field theory have been known for quite some time, deriving them for specific models has often been difficult in practice. This is mainly due to the fact that, albeit straightforward, the involved calculations are quite long, tedious and prone to error. The present work is an attempt to facilitate the practical use of the renormalization group equations in model building. To that end, we have developed two completely independent sets of programs written in Python and Mathematica, respectively. The Mathematica scripts will be part of an upcoming release of SARAH 4. The present article describes the collection of Python routines that we dubbed PyR@TE which is an acronym for "Python Renormalization group equations At Two-loop for Everyone". In PyR@TE, once the user specifies the gauge group and the particle content of the model, the routines automatically generate the full two-loop renormalization group equations for all (dimensionless and dimensionful) parameters. The results can optionally be exported to Latex and Mathematica, or stored in a Python data structure for further processing by other programs. For ease of use, we have implemented an interactive mode for PyR@TE in form of an IPython Notebook. As a first application, we have generated with PyR@TE the renormalization group equations for several non-supersymmetric extensions of the Standard Model and found some discrepancies with the existing literature.
Florian Lyonnet; Ingo Schienbein; Florian Staub; Akin Wingerter
Accelerated Stress Testing and Diagnostic Analysis of Degradation in CdTe Solar Cells
The primary goal of this study was to ascertain the presence and types of mechanisms affecting CdS/CdTe device stability in the temperature range of 60 to 120 ..deg..C. It should be noted that the results presented were specific to cells made using the specific growth conditions described.
Albin, D. S.
We discuss typical and alternative procedures to analyze time-resolved photoluminescence (TRPL) measurements of minority carrier lifetime (MCL) with the hope of enhancing our understanding of how this technique may be used to better analyze CdTe photovoltaic (PV) device functionality. Historically, TRPL measurements of the fast recombination rate (t1) have provided insightful correlation with broad device functionality. However, we have more recently found that t1 does not correlate as well with smaller changes in device performance, nor does it correlate well with performance differences observed between superstrate and substrate CdTe PV devices. This study presents TRPL data for both superstrate and substrate CdTe devices where both t1 and the slower TRPL decay (t2) are analyzed. The study shows that changes in performance expected from small changes in device processing may correlate better with t2. Numerical modeling further suggests that, for devices that are expected to have similar drift field in the depletion region, effects of changes in bulk MCL and interface recombination should be more pronounced in t2. Although this technique may provide future guidance to improving CdS/CdTe device performance, it is often difficult to extract statistically precise values for t2, and therefore t2 data may demonstrate significant scatter when correlated with performance parameters.
Gessert, T. A.; Dhere, R. G.; Duenow, J. N.; Kuciauskas, D.; Kanevce, A.; Bergeson, J. D.
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
B-54 Pre-Combustion membranes u.s. DePartment of energy aDvanCeD Carbon DioxiDe CaPture r&D Program: teChnology uPDate, may 2013 aDvanCeD hyDrogen transPort membranes for Coal...
Search for supersymmetric charged Higgs bosons at the TeVatron
The data collected at the TeVatron RunIIa have been used to look for supersymmetric charged Higgs boson and Left-Right suspersymmetric doubly charged Higgs boson. No signal of such bosons has been found and this note reports on the current analyses and their observed excluded domains in models parameter space.
Grenier, Gerald; /Lyon, IPN
Search for supersymmetric charged Higgs bosons at the TeVatron
The data collected at the TeVatron RunIIa have been used to look for supersymmetric charged Higgs boson and Left-Right suspersymmetric doubly charged Higgs boson. No signal of such bosons has been found and this note reports on the current analyses and their observed excluded domains in models parameter space.
Gerald Grenier
Search for supersymmetric charged Higgs bosons at the TeVatron
The data collected at the TeVatron RunIIa have been used to look for supersymmetric charged Higgs boson and Left-Right suspersymmetric doubly charged Higgs boson. No signal of such bosons has been found and this note reports on the current analyses and their observed excluded domains in models parameter space.
Grenier, Gerald
Degradation and Capacitance-Voltage Hysteresis in CdTe Devices: Preprint
CdS/CdTe cells on CTO/ZTO TCO show greater intial performance than SnO2-gased substrates due to superior optical and electrical properties of the oxide layers and more rigorous CdCl2 processing. Performance unfiormity was a problem.
Albin, D. S.; Dhere, R. G.; Glynn, S. C.; DelCueto, J.; Metzger W. K.
p-Doping limit and donor compensation in CdTe polycrystalline thin film solar cells
everything accelerates. ARCO solar produces more than 1 MW PV cells in `80, being the first in the world, the Million Solar Roofs in the US, and many more. Besides these programs, the efficiency of CdTe thin film PV energy source is the photovoltaic (PV) cell, which converts sunlight to electrical current, without any
Bieber, Michael
In this paper, we report large mid-wave infrared photoconductivity in highly textured, nanocrystalline PbTe films thermally evaporated on Si at room temperature. Responsivity as high as 25 V/W is measured at the 3.5 ?m ...
Wang, Jianfei
NIST Optical grating scatterometry
Science Conference Proceedings (OSTI)
... It is essential that these limits be determined so that the industry can develop alternative solutions. ... pml. Facilities/Tools Used: ...
Design and Test of a 100MW X Band TE01 Window
Science Conference Proceedings (OSTI)
Research at Stanford Linear Accelerator Center (SLAC) is in progress on a TeV-scale linear collider that will operate at 5-10 times the energy of present generation accelerators. This will require development of high power X-Band sources generating 50-100 MW per source. Conventional pillbox window designs are capable of transmitting peak rf powers up to about 30 MW, well below the desired level required for the use of a single window per tube. SLAC has developed a 75 MW TE{sub 01} window [1] that uses a 'traveling wave' design to minimize fields at the window face. Irises match to the dielectric window impedance, resulting in a pure traveling wave in the ceramic and minimum fields on the window face. The use of the TE{sub 01} mode also has zero electric field on the braze fillet. Unfortunately, in-band resonances prevented this window design from achieving the desired 75MW power level. It was believed the resonances resulted from sudden steps in the circular guide to match the 38mm input diameter to the overmoded (TE{sub 01} and TE{sub 02} mode propagating) 65 mm diameter of the window ceramic. Calabazas Creek Research Inc. is currently developing a traveling wave window using compact, numerically optimized, parabolic tapers to match the input diameter of 38mm to the window ceramic diameter of 76mm (Figure 1). The design is projected to handle 100 MW of pulse power with a peak field at the window face of 3.6 MV/m. Cold test of the window has shown the return loss to be better than -25 dB over a 100 MHz bandwidth and to be resonance free (Figure 2). The window is scheduled for high-power testing in July 2003 at the SLAC.
Neilson, J.; Ives, L.; Tantawi, S.G.; /Calabazas Creek Res., Saratoga /SLAC
An electrochemical process has been successfully developed for the reproducible deposition of ZnTe and copper-doped ZnTe films suitable as transparent ohmic contacts for CdS/CdTe solar cells. The development of this method and optimization of key processing steps in the fabrication of CdS/CdTe/ZnTe:Cu devices has allowed IEC to achieve cell performance results of FF>70% and {eta} {approximately}10%. Preliminary efforts have indicated that the deposition methods investigated are potentially feasible for the formation of other II-VI compounds for use in polycrystalline thin film solar devices and should be the focus of future work.
Birkmire, R.W.; McCandless, B.E.; Yokimcus, T.A.; Mondal, A. [Delaware Univ., Newark, DE (United States). Inst. of Energy Conversion
Band offsets for mismatched interfaces: The special case of ZnO on CdTe (001)
High-quality planar interfaces between ZnO and CdTe would be useful in optoelectronic applications, but appear difficult to achieve given the rather different crystal structures (CdTe is zinc blende with cubic lattice constant a = 6.482 �, ZnO is hexagonal wurtzite with a = 3.253 � and c = 5.213 �.) However, ZnO has been reported to occur in some epitaxially stabilized films in the zinc blende structure with an fcc primitive lattice constant close to the hexagonal a value. Observing that this value equals half of the CdTe cubic lattice constant to within 1%, we propose that (001)-oriented cubic ZnO films could be grown epitaxially on a CdTe (001) surface in an R45� ?2??2 configuration. Many terminations and alignments (in-plane fractional translations) are possible, and we describe density-functional total-energy electronic-structure calculations on several configurations to identify the most likely form of the interface, and to predict valence-band offsets between CdTe and ZnO in each case. Growth of ZnO on Te-terminated CdTe (001) is predicted to produce small or even negative (CdTe below ZnO) valence band offsets, resulting in a Type I band alignment. Growth on Cd-terminated CdTe is predicted to produce large positive offsets for a type II alignment as needed, for example, in solar cells. We also describe recent experiments that corroborate some of these predictions.
Jaffe, John E.; Kaspar, Tiffany C.; Droubay, Timothy; Varga, Tamas
Crystals and polycrystalline powders of two new oxide materials, Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}, have been synthesized by hydrothermal and solid-state methods. The materials were structurally characterized by single-crystal X-ray diffraction. Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10} exhibit one dimensional anionic slabs of [CuTeO{sub 6}]{sup 4-} and [CuTe{sub 2}O{sub 10}]{sup 6-}, respectively. Common to both slabs is the occurrence of Cu{sup 2+}O{sub 4} distorted squares and Te{sup 6+}O{sub 6} octahedra. The slabs are separated by Tl{sup +} cations. For Tl{sub 4}CuTeO{sub 6}, magnetic measurements indicate a maximum at {approx}8 K in the temperature dependence of the susceptibility. Low temperature neutron diffraction data confirm no long-range magnetic ordering occurs and the susceptibility was adequately accounted for by fits to a Heisenberg alternating chain model. For Tl{sub 6}CuTe{sub 2}O{sub 10} on the other hand, magnetic measurements revealed paramagnetism with no evidence of long-range magnetic ordering. Infrared, UV-vis spectra, thermogravimetric, and differential thermal analyses are also reported. Crystal data: Tl{sub 4}CuTeO{sub 6}, Triclinic, space group P-1 (No. 2), a=5.8629(8) A, b=8.7848(11) A, c=9.2572(12) A, {alpha}=66.0460(10), {beta}=74.2010(10), {gamma}=79.254(2), V=417.70(9) A{sup 3}, and Z=2; Tl{sub 6}CuTe{sub 2}O{sub 10}, orthorhombic, space group Pnma (No. 62), a=10.8628(6) A, b=11.4962(7) A, c=10.7238(6) A, V=1339.20(13) A{sup 3}, and Z=4. - Graphical Abstract: Two new oxide materials, Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}, have been synthesized and characterized. The materials exhibit one dimensional crystal structures consisting of CuO{sub 4} and TeO{sub 6} polyhedra. Highlights: Black-Right-Pointing-Pointer Two New Tl-Te-Cu-oxides have been synthesized and structurally characterized. Black-Right-Pointing-Pointer For Tl{sub 4}CuTeO{sub 6}, magnetic measurements indicate a maximum at {approx}8 K. Black-Right-Pointing-Pointer Low temperature neutron diffraction data confirm no long-range magnetic ordering. Black-Right-Pointing-Pointer For Tl{sub 6}CuTe{sub 2}O{sub 10} magnetic measurements revealed no long-range magnetic ordering.
Yeon, Jeongho; Kim, Sang-Hwan [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States)] [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States); Green, Mark A. [Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742-2115 and NIST Center for Neutron Research, National Institute of Standard and Technology, 100 Bureau Drive, Gaithersburg, MD 20899-6103 (United States)] [Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742-2115 and NIST Center for Neutron Research, National Institute of Standard and Technology, 100 Bureau Drive, Gaithersburg, MD 20899-6103 (United States); Bhatti, Kanwal Preet; Leighton, C. [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 (United States)] [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 (United States); Shiv Halasyamani, P., E-mail: firstname.lastname@example.com [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States)
During the second quarter of this program primary emphasis was put into depositing and evaluating both n and p-type CdTe films on a variety of conducting and non-conducting substrates. Improvements in the deposition apparatus permitted preparation of a large number of CdTe films and numerous analytic techniques available at Tufts University were utilized to examine these films. It was found that the introduction of a thin (100 A). In layer between the ITO and the CdTe significantly reduced the previously observed barrier present at the ITO/n-CdTe interface without adversely reducing optical transmission. While the resistivity of the films is still rather high, very recent results show that proper changes in procedure are capable of markedly lowering the resistivity. Preliminary Schottky barrier devices have been made which show promising photovoltaic characteristics.
Serreze, H.B.; Entine, G.; Goldner, R.B.
CdS/CdTe cells deposited on CTO/ZTO TCO substrates show greater degradation than similar devices fabricated on cSnO2/iSnO2 substrates.
Albin, D. S.; Dhere, R. G.; Glynn, S. C.; Metzger, W. K.
On 30 November, energy record for the LHC, twin beams at 1.18 TeV
Soon after midnight on November 30 the LHC beats its new world record with two beams ramped to 1.18 TeV simultaneously. The beams were dumped 45 minutes later.
CERN Photo Service
Thin Metal Oxide Films to Modify a Window Layer in CdTe-Based Solar Cells for Improved Performance
Science Conference Proceedings (OSTI)
We report on CdS/CdTe photovoltaic devices that contain a thin Ta2O5 film deposited onto the CdS window layer by sputtering. We show that for thicknesses below 5 nm, Ta2O5 films between CdS and CdTe positively affect the solar cell performance, improving JSC, VOC, and the cell power conversion efficiency despite the insulating nature of the interlayer material. Using the Ta2O5 interlayer, a VOC gain of over 100 mV was demonstrated compared to a CdTe/CdS baseline. Application of a 1nm Ta2O5 interlayer enabled the fabrication of CdTe solar cells with extremely thin (less than 30 nm) CdS window layers. The efficiency of these cells exceeded that of a base line cell with 95 nm of CdS.
Lemmon, John P.; Polikarpov, Evgueni; Bennett, Wendy D.; Kovarik, Libor
Performance improvement of Ge-Sb-Te material by GaSb doping for phase change memory
Effects of GaSb doping on phase change characteristics of Ge-Sb-Te material are investigated by in situ resistance and x-ray diffraction measurement, optical spectroscopy, and x-ray photoelectron spectroscopy. The crystallization temperature and data retention of Ge-Sb-Te material increase significantly by the addition of GaSb, which results from the high thermal stability of amorphous GaSb. In addition, GaSb-doped Ge-Sb-Te material exhibits faster crystallization speed due to the change in electronic states as a result of the formation of chemical bonds with Ga element. Incorporation of GaSb is highly effective way to enhance the comprehensive performance of Ge-Sb-Te material for phase change memory.
Lu, Yegang [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China) [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Faculty of Information Science and Engineering, Ningbo University, Ningbo 315211 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Zhonghua; Song, Sannian; Cheng, Limin; Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)] [State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Shen, Xiang; Wang, Guoxiang; Dai, Shixun [Faculty of Information Science and Engineering, Ningbo University, Ningbo 315211 (China)] [Faculty of Information Science and Engineering, Ningbo University, Ningbo 315211 (China)
Measurement of the W+W- Cross Section in ?s=7??TeV pp Collisions with ATLAS
This Letter presents a measurement of the W[superscript +]W[superscript -] production cross section in ?s=7??TeV pp collisions by the ATLAS experiment, using 34??pb[superscript -1] of integrated luminosity produced by the ...
Taylor, Frank E.
An impurity migration model for systems with material interfaces is applied to Cu migration in CdTe solar cells. In the model, diffusion fluxes are calculated from the Cu chemical potential gradient. Inputs to the model include Cu diffusivities, solubilities, and segregation enthalpies in CdTe, CdS and contact materials. The model yields transient and equilibrium Cu distributions in CdTe devices during device processing and under field-deployed conditions. Preliminary results for Cu migration in CdTe PV devices using available diffusivity and solubility data from the literature show that Cu segregates in the CdS, a phenomenon that is commonly observed in devices after back-contact processing and/or stress conditions.
Teeter, G.; Asher, S.
N-type Bi?Te?.?Se?.? bulk thermoelectric materials with peak ZT values up to ?1 were examined by transmission electron microscopy and electron diffraction. Two nanostructural features were found: (i) a structural modulation ...
Carlton, Chris E.
A comprehensive series of experiments was performed with the aim of optimizing parameters in the chemical spray deposition (CSD) of CdTe thin films. Two approaches have shown great promise. X-ray diffraction analysis has shown that CdTe can be produced from solutions containing CdCl/sub 2/ and (NH/sub 4/)TeO/sub 4/ with either hydrazine dihydrochloride or oxalic acid as the reducing agent. Films produced from the oxalic acid experiments have yielded encouraging infrared scans, and as a result this approach has received the most effort. In addition, good quality, photoconductive, CdS films have been produced via traditional methods and characterized using optical and electrical measurements. Overall film uniformity for both CdS and CdTe has been improved by the installation of a stainless steel, gravity fed, spray nozzle and mechanical linkage.
Sienkiewicz, P.; Lis, S.; Serreze, H.B.; Entine, G.
Expanding the Limits of CdTe PV Performance: Phase I Annual Report, 7 February 2006 - 30 June 2007
First Solar made 9 CdTe PV devices; found two front- and one back-side structures that show improved Jsc and Voc, respectively, compared to base device structure; best cell efficiency was 14.13%.
Meyers, P.
CdSe/CdTe type-II superlattices grown on GaSb (001) substrates by molecular beam epitaxy
CdSe/CdTe superlattices are grown on GaSb substrates using molecular beam epitaxy. X-ray diffraction measurements and cross-sectional transmission electron microscopy images indicate high crystalline quality. Photoluminescence (PL) measurements show the effective bandgap varies with the superlattice layer thicknesses and confirm the CdSe/CdTe heterostructure has a type-II band edge alignment. The valence band offset between unstrained CdTe and CdSe is determined as 0.63 {+-} 0.06 eV by fitting the measured PL peak positions using the envelope function approximation and the Kronig-Penney model. These results suggest that CdSe/CdTe superlattices are promising candidates for multi-junction solar cells and other optoelectronic devices based on GaSb substrates.
Li Jingjing; Liu Shi; Wang Shumin; Ding Ding; Johnson, Shane R.; Zhang Yonghang [Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287 (United States); School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Liu Xinyu; Furdyna, Jacek K. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Smith, David J. [Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287 (United States); Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)
An impurity migration model for systems with material interfaces is applied to Cu migration in CdTe solar cells. In the model, diffusion fluxes are calculated from the Cu chemical potential gradient. Inputs to the model include Cu diffusivities, solubilities, and segregation enthalpies in CdTe, CdS and contact materials. The model yields transient and equilibrium Cu distributions in CdTe devices during device processing and under field-deployed conditions. Preliminary results for Cu migration in CdTe photovoltaic devices using available diffusivity and solubility data from the literature show that Cu segregates in the CdS, a phenomenon that is commonly observed in devices after back-contact processing and/or stress conditions.
Teeter, G.; Asher, S.
Glass-like phonon scattering from a spontaneous nanostructure in AgSbTe2
Science Conference Proceedings (OSTI)
Materials with very low thermal conductivity are of high interest for both thermoelectric and optical phase-change applications. Synthetic nanostructuring is most promising to suppress thermal conductivity by scattering phonons, but challenges remain in producing bulk samples. We show that in crystalline AgSbTe2, a spontaneously-forming nanostructure leads to a suppression of thermal conductivity to a glass-like level. Our mappings of phonon mean-free-paths provide a novel bottom- up microscopic account of thermal conductivity, and also reveal intrinsic anisotropies associated with the nanostructure. Ground-state degeneracy in AgSbTe2 leads to the natural formation of nanoscale domains with different orderings on the cation sublattice, and correlated atomic displacements, which efficiently scatter phonons. This mechanism is general and points to a new avenue in nano- scale engineering of materials, to achieve low thermal conductivities for efficient thermoelectric converters and phase-change memory devices.
Abernathy, Douglas L [ORNL; Ehlers, Georg [ORNL; Huq, Ashfia [ORNL; Ma, Jie [ORNL; May, Andrew F [ORNL; McGuire, Michael A [ORNL; Sales, Brian C [ORNL; Delaire, Olivier A [ORNL; Hong, Tao [ORNL; Tian, Wei [ORNL
CdS/CdTe Thin-Film Solar Cell with a Zinc Stannate Buffer Layer
This paper describes an improved CdS/CdTe polycrystalline thin-film solar-cell device structure that integrates a zinc stannate (Zn2SnO4 or ZTO) buffer layer between the transparent conductive oxide (TCO) layer and the CdS window layer. Zinc stannate films have a high bandgap, high transmittance, low absorptance, and low surface roughness. In addition, these films are chemically stable and exhibit higher resistivities that are roughly matched to that of the CdS window layer in the device structure. Preliminary device results have demonstrated that by integrating a ZTO buffer layer in both SnO2-based and Cd2SnO4 (CTO)-based CdS/CdTe devices, performance and reproducibility can be significantly enhanced
Wu, X.; Sheldon, P.; Mahathongdy, Y.; Ribelin, R.; Mason, A.; Moutinho, H. R.; Coutts, T. J.
Effect of Extended Defects in Planar and Pixelated CdZnTe Detectors
Science Conference Proceedings (OSTI)
We evaluated a spectroscopy-grade 15 x 15 x 7 mm{sup 3} CdZnTe (CZT) crystal with a high {mu}{tau}-product, > 10{sup -2} cm{sup 2}/V, but impaired by microscopic extended defects, such as walls of dislocations, low-angle and sub-grain boundaries, and Te inclusions. First, we evaluated a planar detector fabricated from this crystal using a Microscale X-ray Detector Mapping (MXDM) technique. Then, we fabricated from the same crystal a pixel detector to study local non-uniformities of the electric field. The measured X-ray response maps confirmed the presence of non-uniformities in the charge transport, and they showed that the global- and local-distortions of the internal E-field correlated to the extended defects and space-charge buildup on the side surfaces.
C Camarda; K Andreini; A Bolotnikov; Y Cui; A Hossain; R Gul; K Kim; L Marchini; L Xu; et al.
Thermoelectric properties of AgGaTe$_2$ and related chalcopyrite structure materials
Science Conference Proceedings (OSTI)
We present an analysis of the potential thermoelectric performance of p-type AgGaTe$_{2}$, which has already shown a $ZT$ of 0.8 with partial optimization, and observe that the same band structure features, such as a mixture of light and heavy bands and isotropic transport, that lead to this good performance are present in certain other ternary chalcopyrite structure semiconductors. We find that optimal performance of AgGaTe$_2$ will be found for hole concentrations between 4 $\\times 10^{19}$ and 2 $\\times 10^{20}$cm$^{-3}$ at 900 K, and 2 $\\times 10^{19}$ and 10$^{20}$ cm$^{-3}$ at 700 K, and that certain other chalcopyrite semiconductors might show good thermoelectric performance at similar doping ranges and temperatures if not for higher lattice thermal conductivity.
Parker, David S [ORNL; Singh, David J [ORNL
Photoluminescence studies of type-II CdSe/CdTe superlattices
CdSe/CdTe type-II superlattices grown on GaSb substrates by molecular beam epitaxy are studied using time-resolved and steady-state photoluminescence (PL) spectroscopy at 10 K. The relatively long carrier lifetime of 188 ns observed in time-resolved PL measurements shows good material quality. The steady-state PL peak position exhibits a blue shift with increasing excess carrier concentration. Self-consistent solutions of the Schroedinger and Poisson equations show that this effect can be explained by band bending as a result of the spatial separation of electrons and holes, which is critical confirmation of a strong type-II band edge alignment between CdSe and CdTe.
Li Jingjing; Johnson, Shane R.; Wang Shumin; Ding Ding; Ning Cunzheng; Zhang Yonghang [Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287-5706 (United States); School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States); Yin Leijun [Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287-5706 (United States); Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); Skromme, B. J. [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States); Liu Xinyu; Furdyna, Jacek K. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
Search for microscopic black holes in pp collisions at sqrt(s) = 8 TeV
A search for microscopic black holes and string balls is presented, based on a data sample of pp collisions at sqrt(s) = 8 TeV recorded by the CMS experiment at the Large Hadron Collider and corresponding to an integrated luminosity of 12 inverse femtobarns. No excess of events with energetic multiparticle final states, typical of black hole production or of similar new physics processes, is observed. Given the agreement of the observations with the expected standard model background, which is dominated by QCD multijet production, 95% confidence limits are set on the production of semiclassical or quantum black holes, or of string balls, corresponding to the exclusions of masses below 4.3 to 6.2 TeV, depending on model assumptions. In addition, model-independent limits are set on new physics processes resulting in energetic multiparticle final states.
CMS Collaboration
Investigation of Cd1-xMgxTe Alloys for Tandem Solar Cell Applications (Poster)
Fabrication and characterization of Cd{sub 1-x}Mg{sub x}Te(CMT) alloys and to determine their potential for device applications. Main emphasis is on the development of the devices in 1.5 to 1.8 eV range for the top cell of two-junction tandem solar cells. The conclusions are: (1) CMT alloy films with a wide composition range were fabricated; (2) the optical band gap shows a systematic variation with composition and CMT alloy films withstood the commonly used device processing steps for CdTe; and (3) they have fabricated cells with 5% efficiency in the energy gap range of 1.5 to 1.7 eV and established the viability of CMT for device applications.
Dhere, R.; Ramanathan, K.; Scharf, J.; Moutinho, H.; To, B.; Duda, A.; Noufi, R.
EE&RE, Session: CdTe - Progress and Roadmap Alignment (Presentation)
This project supports the Solar America Initiative by: (1) assistance to SAI Incubators (Primestar Solar, AvA Solar); (2) providing industry with baseline understanding of CdS/CdTe device formation and reliability--incorporation of low-cost, high quality TCOs, functionality and options for buffer layers, effect of various CdS options, effect of and importance CdSTe alloy formation, effect and options for CdCl{sub 2} treatment, effect and options for back contact, and effect of residual impurities during all stages of device formation; (3) understanding modes and mechanisms of cell-level stability; and (4) establishment of CdTe PDIL Tool for rapid material and process screening.
Gessert, T.
The High-Resolution Lightweight Telescope for the EUV (HiLiTE)
The High-resolution Lightweight Telescope for the EUV (HiLiTE) is a Cassegrain telescope that will be made entirely of Silicon Carbide (SiC), optical substrates and metering structure alike. Using multilayer coatings, this instrument will be tuned to operate at the 465 {angstrom} Ne VII emission line, formed in solar transition region plasma at {approx}500,000 K. HiLiTE will have an aperture of 30 cm, angular resolution of {approx}0.2 arc seconds and operate at a cadence of {approx}5 seconds or less, having a mass that is about 1/4 that of one of the 20 cm aperture telescopes on the Atmospheric Imaging Assembly (AIA) instrument aboard NASA's Solar Dynamics Observatory (SDO). This new instrument technology thus serves as a path finder to a post-AIA, Explorer-class missions.
Martinez-Galarce, D S; Boerner, P; Soufli, R; De Pontieu, B; Katz, N; Title, A; Gullikson, E M; Robinson, J C; Baker, S L
Crystallization Times of Ge-Te Phase Change Materials as a Function of Composition
Science Conference Proceedings (OSTI)
The crystallization times of Ge-Te phase change materials with variable Ge concentrations (29.5-72.4 at. %) were studied. A very strong dependence of the crystallization time on the composition for as-deposited, amorphous films was confirmed, with a minimum for the stoichiometric composition GeTe. The dependence is weaker for melt-quenched, amorphous material and crystallization times are between one to almost four orders of magnitude shorter than for as-deposited materials. This is promising for applications because recrystallization from the melt-quenched phase is the relevant process for optical and solid state memory, and fast crystallization and weak dependence on compositional variations are desirable.
S Raoux; H Cheng; M Caldwell; H Wong
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
sorbents sorbents B-14 Pre-Combustion sorbents u.s. DePartment of energy aDvanCeD Carbon DioxiDe CaPture r&D Program: teChnology uPDate, may 2013 aDvanCeD Carbon DioxiDe CaPture teChnology for low-rank Coal integrateD gasifiCation CombineD CyCle (igCC) systems primary project goals TDA will investigate the technical and economic advantages of using an integrated carbon dioxide (CO 2 ) sorbent and water-gas shift (WGS) catalyst system in an integrated gasifi- cation combined cycle (IGCC) power plant, fueled with low-rank coal, and designed to capture more than 90% of the CO 2 emissions. technical goals * TDA will evaluate the physical mix of the sorbent and catalyst pellets within the same
Search for new particles decaying to diject in 7 TeV proton-proton collisions at CMS
This thesis presents a measurement of the dijet invariant mass spectrum and search for new particles decaying to dijets at CMS in 7 TeV pp collisions using data corresponding to an integrated luminosity of 2.875 pb{sup -1}. The measured dijet mass distribution is compared to QCD prediction from PYTHIA . It is required the pseudorapidity separation of the two jets to satisfy |Dh| < 1.3 with each jet inside the region of |{eta}| < 2.5. The observed dijet mass spectrum is fitted by a smooth function to search for dijet resonances. Since there is no evidence for dijet resonances, the upper limits at 95% Confidence Level (C.L.) on the resonance cross section are set. These generic cross section limits are compared with theoretical predictions for the cross section for several models of new particles: string resonances, axigluons, colorons, excited quarks, E{sub 6} diquarks, Randall-Sundrum gravitons, W' and Z'. It is excluded at 95% C.L. string resonances in the mass range 0.50 < M(S) < 2.50 TeV, excited quarks in the mass range 0.50 < M(q*) < 1.58 TeV, axigluons and colorons in the mass ranges 0.50 < M(A) < 1.17 TeV and 1.47 < M(A) < 1.52 TeV, and E{sub 6} diquarks in the mass ranges 0.50 < M(D) < 0.58 TeV, 0.97 < M(D) < 1.08 TeV, and 1.45 < M(D) < 1.60 TeV. These exclusions extend previously published limits on all models.
Ozturk, Sertac; /Cukurova U.
The focus of this project is the open-circuit voltage of the CdTe thin-film solar cell. CdTe continues to be one of the leading materials for large-scale cost-effective production of photovoltaics, but the efficiency of the CdTe solar cell has been stagnant for the last few years. At the manufacturing front, the CdTe technology is fast paced and moving forward with U.S.-based First Solar LLC leading the world in CdTe module production. To support the industry efforts and continue the advancement of this technology, it will be necessary to continue improvements in solar cell efficiency. A closer look at the state-of-the-art performance levels puts the three solar cell efficiency parameters of short-circuit current density (JSC), open-circuit voltage (VOC), and fill factor (FF) in the 24-26 mA/cm2, 844?850 mV, and 74%-76% ranges respectively. During the late 1090s, efforts to improve cell efficiency were primarily concerned with increasing JSC, simply by using thinner CdS window layers to enhance the blue response (<510 nm) of the CdTe cell. These efforts led to underscoring the important role 'buffers' (or high-resistivity transparent films) play in CdTe cells. The use of transparent bi-layers (low-p/high-p) as the front contact is becoming a 'standard' feature of the CdTe cell.
Ferekides, C. S.; Morel, D. L.
In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 degrees C.
Albin, D.; del Cueto, J.
EGS4 calculations for a Cd-Zn-Te detector to measure synchrotron radiation at PEP-II
Calculations have been performed with the EGS4 Code System for a CdZnTe semiconductor detector to be used in background studies of synchrotron radiation at PEP-II. The simulations take into account K-shell fluorescent-photon production in a CdZnTe mixture, electron-hole pair collection and electronic-noise broadening. The results are compared with measurements made with encapsulated {sup 241}Am, {sup 133}Ba and {sup 109}Cd sources.
Nelson, W.R. [Stanford Univ., CA (US). Stanford Linear Accelerator Center; Borak, T.; Malchow, R.; Toki, W. [Colorado State Univ., Fort Collins, CO (US); Kadyk, J. [Lawrence Berkeley National Lab., CA (US)
EGS4 CALCULATIONS FOR A Cd-Zn-Te DETECTOR TO? y MEASURE SYNCHROTRON RADIATION AT PEP-II
Calculations have been performed with the EGS4 Code System for a CdZnTe semiconductor detector to be used in background studies of synchrotron radiation at PEP-II. The simulations take into account K-shell uorescent-photon production in a CdZnTe mixture, electron-hole pair collection and electronic-noise broadening. The results are compared with measurements made with encapsulated 241 Am, 133 Ba and 109 Cd sources.
W. R. Nelson; T. Borak; R. Malchow; W. Toki; J. Kadyk
Beam-induced backgrounds in the CLIC 3 TeV CM energy interaction region
Luminosity spectrum and accelerator background levels strongly influence the experimental conditions and have an important impact on detector design. The expected rates of the main beam-beam products at CLIC 3 TeV CM energy, taking into account for machine imperfections, are computed. Among the other machine-induced background the photon fans from the Incoherent Synchrotron Radiation (ISR) photons emitted in the final doublet are evaluated.
B. Dalena; J. Esberg; D. Schulte
Electron scattering by acceptor centers in p-Ag{sub 2}Te at low temperatures
Science Conference Proceedings (OSTI)
Resonant electron scattering in p-Ag{sub 2}Te at acceptor concentrations N{sub a} < 4.2 x 10{sup 16} cm{sup -3} has been observed in the temperature range of 50-80 K. The contribution of the resonant scattering to the temperature dependences of the conductivity {sigma}(T) and thermopower {alpha}{sub 0}(T) has been calculated. It is shown that this contribution exceeds that of charge carrier scattering by acoustic phonons.
Aliev, F. F., E-mail: firstname.lastname@example.com; Jafarov, M. B.; Askerova, G. Z. [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan); Gojaev, E. M. [Azerbaijan Technical University (Azerbaijan)
Luminosity limitations at the multi-TeV linear collider energy frontier
To achieve the desired high luminosity in e+ e- linear colliders with centre-of-mass energies above the TeV scale, careful optimisation of the beam parameters is necessary. Constraints arising from the RF structure design, the beam-beam interaction, the damping ring and the beam delivery system have to be taken into account and compromises between different requirements have to be found. The nature of these different constraints is discussed and the resulting limits for the luminosity are detailed.
Schulte, Daniel
Fabrication of stable, large-area, thin-film CdTe photovoltaic modules
Solar Cells, Inc (SCI) has a program to produce 60 cm X 120 cm solar modules based on CdTe films. The method of choice for semiconductor deposition is condensation from high temperature vapor's. Early work focussed on Close Spaced Sublimation and Chemical Vapor Deposition using elemental sources, but later equipment designs no longer strictly conform to either category. Small area efficiency has been confirmed by NREL at 9.3% on a 0.22 cm{sup 2} device (825 mV Voc, 18.2 mA/cm{sup 2} Jsc, and 0.62 FF) deposited on a 100 cm{sup 2} substrate. On 8 cell, 64 cm{sup 2} submodules, the best result to date is 7.3% (5.9 V Voc, 130 mA Isc, and 0.61 FF). CdS, CdTe, and ZnTe films have been deposited onto 60 cm X 120 cm substrates - single cells produced from this material have exceeded 8% efficiency, 64 cm{sup 2} submodules have exceeded 5%. Module efficiency is limited by mechanical defects - mostly shunts - associated with processing after deposition of the semiconductor layer's. Present best result is 1.4% total area efficiency. In anticipation of more advanced designs, CdTe films have also been deposited from apparatus employing elemental sources. This project is in an early stage and has produced only rudimentary results. A pro-active Safety, Health, Environmental and Disposal program has been developed. Results to date indicate that both employees and the environment have been protected against overexposure to hazards including toxic chemicals.
Nolan, J.F.; Meyers, P.V. (Solar Cells, Inc., Toledo, OH (United States))
Thermographic analyses of the growth of Cd1-xZnxTe single crystals
Bulk Cd1-xZnxTe (0 Kopach, O.V.; Bolotnikov, A.; Shcherbak, Larysa P.; Fochuk, Petro M.; and James, Ralph B. 2010-08-01T23:59:59.000Z
Photon + Jet production at sqrt{s}=1.96 TeV
Prompt photon production results by the CDF and D\\OCollaborations in the Tevatron Run II at a center of mass energy of $\\sqrt{s}$=1.96 TeV are presented. Cross sections for central isolated photons, photon+jet production and photons produced in association with a heavy flavor quark are reported. The measurements are compared to Next-to-Leading order perturbative QCD predictions.
C. Deluca
TeV Observations of Markarian 501 with the Milagrito Water Cherenkov Detector
The Milagrito water Cherenkov detector near Los Alamos, New Mexico, operated as a sky monitor at energies of a few TeV between February 1997 and May 1998 including the period of the strong, long-lasting 1997 flare of Markarian 501. Milagrito served as a test run for the full Milagro detector. An event excess with a significance of 3.7 sigma from Markarian 501 was observed, in agreement with expectations.
R. Atkins
Study of Four Young TeV Pulsar Wind Nebulae with a Spectral Evolution Model
We study four young Pulsar Wind Nebulae (PWNe) detected in TeV gamma-rays, G21.5-0.9, G54.1+0.3, Kes 75, and G0.9+0.1, using the spectral evolution model developed and applied to the Crab Nebula in our previous work. We model the evolution of magnetic field and particle distribution function inside a uniformly expanding PWN considering a time-dependent injection from the pulsar and radiative and adiabatic losses. Considering uncertainties in the interstellar radiation field (ISRF) and their distance, we study two cases for each PWN. Because TeV PWNe have a large TeV gamma-rays to X-rays flux ratio, the magnetic energy of the PWNe accounts for only a small fraction of the total energy injected (typically a few x 10^{-3}). The gamma-ray emission is dominated by inverse Compton scattering off the infrared photons of the ISRF. A broken power-law distribution function for the injected particles reproduces the observed spectrum well, except for G0.9+0.1. For G0.9+0.1, we do not need a low energy counterpart because...
Tanaka, Shuta J
Time dependent modelisation of TeV blazars by a stratified jet model
We present a new time-dependent inhomogeneous jet model of non-thermal blazar emission. Ultra-relativistic leptons are injected at the base of a jet and propagate along it. We assume continuous reacceleration and cooling, producing a relativistic quasi-maxwellian (or "pile-up") particle energy distribution. The synchrotron and Synchrotron-Self Compton jet emissivity are computed at each altitude. Klein-Nishina effects as well as intrinsic gamma-gamma absorption are included in the computation. Due to the pair production optical depth, considerable particle density enhancement can occur, particularly during flaring states.Time-dependent jet emission can be computed by varying the particle injection, but due to the sensitivity of pair production process, only small variations of the injected density are required during the flares. The stratification of the jet emission, together with a pile-up distribution, allows significantly lower bulk Lorentz factors, compared to one-zone models. Applying this model to the case of PKS 2155-304 and its big TeV flare observed in 2006, we can reproduce simultaneously the average broad band spectrum of this source from radio to TeV, as well as TeV light curve of the flare with bulk Lorentz factor lower than 15.
Timoth� Boutelier; Gilles Henri; Pierre-Olivier Petrucci
An inhomogeneous jet model for the rapid variability of TeV blazars
We present a new time-dependent inhomogeneous jet model of non-thermal blazar emission, which reproduces the entire spectral energy distribution together with the rapid gamma-ray variability. Ultra-relativistic leptons are injected at the base of a jet and propagate along the jet structure. We assume continuous reacceleration and cooling, producing a relativistic quasi-maxwellian (or "pile-up") particle energy distribution. The synchrotron and Synchrotron-Self Compton jet emissivity are computed at each altitude. Klein-Nishina effects as well as intrinsic gamma-gamma absorption are included in the computation. Due to the pair production optical depth, considerable particle density enhancement can occur, particularly during flaring states. Time-dependent jet emission can be computed by varying the particle injection, but due to the sensitivity of pair production process, only small variations of the injected density are required during the flares. The stratification of the jet emission, together with a pile-up distribution, allows significantly lower bulk Lorentz factors, compared to one-zone models. Applying this model to the case of PKS2155-304 and its big TeV flare observed in 2006, we can reproduce simultaneously the average broad band spectrum of this source as well as the TeV spectra and TeV light curve of the flare with bulk Lorentz factor lower than 15.
Timoth� Boutelier; Gilles Henri; Pierre-Olivier Petrucci
Conductivity anisotropy in the doped Bi{sub 2}Te{sub 3} single crystals
Science Conference Proceedings (OSTI)
Temperature dependences (temperature range T = 0.5-300 K) of resistivity in the plane of layers and in the direction perpendicular to the layers, and the galvanomagnetic effects in undoped and doped Bi{sub 2}Te{sub 3} single crystals are studied (magnetic field H < 80 kOe, T = 0.5-4.2 K). It is shown that upon doping of Bi{sub 2}Te{sub 3} with the Group III atoms (In and B), conductivity anisotropy increases mainly due to an increase in resistivity in the direction perpendicular to the layers. This fact makes it possible to assume that the atoms of these impurities are incorporated mainly into the van der Waal gaps between the layers upon doping. It is also revealed that, upon doping of Bi{sub 2}Te{sub 3} with In and B, the temperature dependence of conductivity becomes weaker, which indicates an increase in the role of scattering by defects in scattering mechanisms. The concentrations and mobilities of charge carriers, values of the Hall factor conditioned by the anisotropy of effective masses and orientation of ellipsoids with respect to crystallographic axes, areas of the extreme section of the Fermi surface by the plane perpendicular to the direction of the magnetic field, and the Fermi energy are evaluated.
Abdullaev, N. A., E-mail: email@example.com; Kakhramanov, S. Sh.; Kerimova, T. G.; Mustafayeva, K. M. [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan); Nemov, S. A. [St. Petersburg State Polytechnical University (Russian Federation)
Overcoming Degradation Mechanisms in CdTe Solar Cells: Final Report, July 1998--September 2001
This report describes the stability of CdTe solar cells, with special focus on possible effects of diffusion from the contact to the absorber towards other cell components. Both whole cells and test systems containing only the ohmic contact and the absorber or only the window were used. We found that NiTe2 is a promising back-contact material. We also found that Cu as such is not the dominant factor in the most common and quickest type of degradation of these cells. An additional factor appears to be the formation of an oxide film on CdTe grains, which can be associated with the formation of the additional back-contact barrier that has been deduced from electrical characterization. Further observations were: Cell degradation appears to be promoted by H2O, O2, and illumination, in that order; less efficient cells are less stable than more efficient ones; some cells have been stabilized by heating in ultra-dry and O2-free inert atmosphere (N2 was used by us) before use, against subsequent degradation; and cells can recover by heating in dry N2 or by sitting on the shelf in ambient atmosphere.
Cahen, D.; Hodes, G.; Gartsman, K.
Effect of Te Inclusions on the Performance of Cdznte Radiation Detectors
Science Conference Proceedings (OSTI)
Te inclusions existing at high concentrations in CdZnTe (CZT) material can degrade the performance of CZT detectors. These microscopic defects trap the free electrons generated by incident radiation, so entailing significant fluctuations in the total collected charge and thereby strongly affecting the energy resolution of thick (long-drift) detectors. Such effects were demonstrated in thin planar detectors, and, in many cases, they proved to be the dominant cause of the low performance of thick detectors, wherein the fluctuations in the charge losses accumulate along the charge's drift path. We continued studying this effect using different tools and techniques. We employed a dedicated beamline recently established at BNL's National Synchrotron Light Source for characterizing semiconductor radiation detectors, along with an IR transmission microscope system, the combination of which allowed us to correlate the concentration of defects with the devices' performances. We present here our new results from testing over 50 CZT samples grown by different techniques. Our goals are to establish tolerable limits on the size and concentrations of these detrimental Te inclusions in CZT material, and to provide feedback to crystal growers to reduce their numbers in the material.
Bolotnikov, A.; Abdul-Jabbar, N; Babalola, O; Camarda, G; Cui, Y; Hossain, A; Jackson, E; Jackson, H; James, J; et. al.
We report here on the major commercialization aspects of thin-film photovoltaic (PV) technologies based on CIGS and CdTe (a-Si and thin-Si are also reported for completeness on the status of thin-film PV). Worldwide silicon (Si) based PV technologies continues to dominate at more than 94% of the market share, with the share of thin-film PV at less than 6%. However, the market share for thin-film PV in the United States continues to grow rapidly over the past several years and in CY 2006, they had a substantial contribution of about 44%, compared to less than 10% in CY 2003. In CY 2007, thin-film PV market share is expected to surpass that of Si technology in the United States. Worldwide estimated projections for CY 2010 are that thin-film PV production capacity will be more than 3700 MW. A 40-MW thin-film CdTe solar field is currently being installed in Saxony, Germany, and will be completed in early CY 2009. The total project cost is Euro 130 million, which equates to an installed PV system price of Euro 3.25/-watt averaged over the entire solar project. This is the lowest price for any installed PV system in the world today. Critical research, development, and technology issues for thin-film CIGS and CdTe are also elucidated in this paper.
Ullal, H. S.; von Roedern, B.
Investigation of Cd1-XMgxTe Alloys for Tandem Solar Cell Applications: Preprint
Theoretical modeling of two-junction tandem solar cells shows that for optimal device performance, the bandgap of the top cell should be in the range of 1.6 to 1.8 eV. Cd1-xMgxTe (CMT) alloys have a lattice constant close to that of CdTe, and the addition of a small amount of Mg changes the bandgap considerably. In this paper, we present our work on developing CMT for solar cell applications. CMT films were prepared by vacuum deposition with co-evaporation of CdTe and Mg on substrates heated to 300-400 C. Films with a composition in the range of x = 0 to 0.66 were fabricated, and optical analysis of the films showed that the bandgap of the samples ranged from 1.5 to 2.3 eV and varied linearly with composition. For the fabrication of devices using these alloy films, we also investigated the effect of post-deposition CdCl2 heat treatment. We have investigated junctions between CdS and CMT alloys in the bandgap range of 1.5 to 1.8 eV for tandem cell applications. We have also worked on the ohmic contacts to the CMT alloy films using Cu/Au bilayers, and the preliminary data shows a significant effect of the contact processing on the device performance.
Dhere, R.; Ramanathan, K.; Scharf, J.; Moutinho, H.; To, B.; Duda, A.; Noufi, R.
This report describes work performed by the Georgia Institute of Technology (GIT) to bring the polycrystalline CdTe cell efficiency a step closer to the practically achievable efficiency of 18% through fundamental understanding of detects and loss mechanisms, the role of chemical and heat treatments, and investigation of now process techniques. The objective was addressed by a combination of in-depth characterization, modeling, materials growth, device fabrication, and `transport analyses of Au/Cu/CdTe/CdS/SnO {sub 2} glass front-wall heterojunction solar cells. GiT attempted to understand the loss mechanism(s) in each layer and interface by a step-by-step investigation of this multilayer cell structure. The first step was to understand, quantify, and reduce the reflectance and photocurrent loss in polycrystalline CdTe solar calls. The second step involved the investigation of detects and loss mechanisms associated with the CdTe layer and the CdTe/CdS interface. The third stop was to investigate the effect of chemical and heat treatments on CdTe films and cells. The fourth step was to achieve a better and reliable contact to CdTe solar cells by improving the fundamental understanding. Of the effects of Cu on cell efficiency. Finally, the research involved the investigation of the effect of crystallinity and grain boundaries on Cu incorporation in the CdTe films, including the fabrication of CdTe solar calls with larger CdTe grain size.
Rohatgi, A.; Chou, H.C.; Kamra, S.; Bhat, A. [Georgia Inst. of Tech., Atlanta, GA (United States)
Polycrystalline thin film CdTe solar cells are one of the leading candidates for terrestrial photovoltaic applications. Theoretical calculations project an efficiency of 27% for single crystal, single junction CdTe cells, and the practically achievable efficiency for polycrystalline CdTe cells is 18-20%. Polycrystalline CdTe cells made by different groups show a significant variation in short circuit currents, open circuit voltages, and cell efficiencies. A better understanding of carrier loss and transport mechanism is crucial for explaining these differences, improving the yield, and bridging the gap between current and practically achievable limits in CdTe cell efficiencies. The goal of this program is to improve the understanding of the loss mechanisms in thin film CdS/CdTe solar cells and to improve their efficiency by characterizing the properties of the films as well as the finished devices.
Rohatgi, A.; Chou, H.C.; Kamra, S.; Bhat, A. [Georgia Institute of Technology, Atlanta, GA (United States)
Research performed at NREL to produce CdS/CdTe devices on St. Gobain coated-glass material to establish a baseline CdS/CdTe device process and determine baseline device performance parameters on St. Gobain material. Performance of these baseline devices compared to similar devices produced by applying the established baseline CdS/CdTe process on alternative St. Gobain coated-glass materials.
Gessert, T.
Science Conference Proceedings (OSTI)
Sb{sub 2}Te{sub 3} and Bi{sub 2}Te{sub 3} thin films were grown at room temperature on SiO{sub 2} and BaF{sub 2} substrates using molecular beam epitaxy. A layer-by-layer growth was achieved such that metallic layers of the elements with 0.2 nm thickness were deposited. The layer structure in the as-deposited films was confirmed by X-ray diffraction and was seen more clearly in Sb{sub 2}Te{sub 3} thin films. Subsequent annealing was done at 250 C for 2 h and produced the Sb{sub 2}Te{sub 3} and Bi{sub 2}Te{sub 3} crystal structure as confirmed by high-energy X-ray diffraction. This preparation process is referred to as nano-alloying and it was demonstrated to yield single-phase thin films of these compounds. In the thin films a significant texture could be identified with the crystal c axis being almost parallel to the growth direction for Sb{sub 2}Te{sub 3} and tilted by about 30{sup o} for Bi{sub 2}Te{sub 3} thin films. In-plane transport properties were measured for the annealed films at room temperature. Both films yielded a charge carrier density of about 2.6 x 10{sup 19} cm{sup -3}. The Sb{sub 2}Te{sub 3} films were p-type, had a thermopower of +130 {micro}V K{sup -1}, and surprisingly high mobilities of 402 cm{sup 2} V{sup -1} s{sup -1}. The Bi{sub 2}Te{sub 3} films were n-type, showed a thermopower of -153 {micro}V K{sup -1}, and yielded significantly smaller mobilities of 80 cm2 V{sup -1} s{sup -1}. The chemical composition and microstructure of the films were investigated by transmission electron microscopy (TEM) on cross sections of the thin films. The grain sizes were about 500 nm for the Sb{sub 2}Te{sub 3} and 250 nm for the Bi{sub 2}Te{sub 3} films. In the Bi{sub 2}Te{sub 3} thin film, energy-filtered TEM allowed to image a Bi-rich grain boundary phase, several nanometers thick. This secondary phase explains the poor mobilities of the Bi{sub 2}Te{sub 3} thin film. With these results the high potential of the nano-alloying deposition technique for growing films with a more complex layer architecture is demonstrated.
Peranio, N.; Winkler, M.; Bessas, D.; Aabdin, Z.; K�nig, J.; B�ttner, H.; Hermann, R.P.; Eibl, O. (Julich); (Tubingen); (Fraunhofer)
International Energy Outlook 1998
Gasoline and Diesel Fuel Update (EIA)
8) 8) Dis tri bu tion Cate gory UC-950 In ter na tional En ergy Out look 1998 April 1998 En ergy In for ma tion Ad min istra tion Of fice of In te grated Analy sis and Fore cast ing U.S. De part ment of En ergy Wash ing ton, DC 20585 This re port was pre pared by the En ergy In for ma tion Ad min istra tion, the in de pend ent sta tis ti cal and ana lyti cal agency within the De part ment of En ergy. The in for ma tion con tained herein should be at trib uted to the En ergy In for ma tion Ad min istra tion and should not be con strued as ad vo cat ing or re flect ing any pol icy po si tion of the De part ment of En ergy or of any other or gani za tion. Con tacts The Inter na tional Energy Out look is pre pared by the Energy Infor ma tion Admin istra tion (EIA). Gen eral
The research by Colorado State University advances the understanding of device stability, efficiency, and process yield for CdTe PV devices.
Sampath, W. S.; Enzenroth, A.; Barth, K.
The Fate of MAb targeted Cd125mTe/ZnS nanoparaticles in vivo
Science Conference Proceedings (OSTI)
Nanoparticles (NP) have potential as carriers for drugs and radioisotopes. Quantitative measures of NP biodistribution in vivo are needed to determine the effectiveness of these carriers. We have used a model system of radiolabeled quantum dots to document the competition between efficient vascular targeting and interaction of the NP with the reticuloendothelial (RE) system. We have prepared (125m)Te-labeled CdTe NP that are capped with ZnS. Te-125m has a half-life and decay characteristics very similar to those for (125)I. The synthesized particles are stable in aqueous solution and are derivatized with mercaptoacetic acid and then conjugated with specific antibody. To evaluate specific targeting, we used the monoclonal antibody MAb 201B that binds to murine thrombomodulin expressed in the lumen of lung blood vessels. The MAb-targeted NP were tested for targeting performance in vivo using single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging, tissue autoradiography and standard organ biodistribution techniques. Biodistribution was also determined in mice that had been depleted of phagocytic cells by use of clodronate-loaded liposomes. Cd(125m)Te/ZnS NP coupled with MAb 201B retained radioisotope and antibody activity and accumulated in lung (>400% injected dose [ID]/g) within 1 h of intravenous injection. Control antibody-coupled NP did not accumulate in lung (<10% ID/g) but accumulated in liver and spleen. Images from microSPECT/CT and autoradiography studies of the targeted NP document this specific uptake and demonstrate uniform distribution in lung with minor accumulation in liver and spleen. Within a few hours, a large fraction of lung-targeted NP redistributed to spleen and liver or was excreted. We hypothesized that NP attract phagocytic cells that engulfed and removed them from circulation. This was confirmed by comparing biodistribution of targeted NP in normal mice versus those depleted of phagocytic cells. In mice treated with clodronate liposomes, accumulation of NP in liver was reduced by fivefold, while accumulation in lung at 1 h was enhanced by approximately 50%. By 24 h, loss of the targeted NP from lung was inhibited by several-fold, while accumulation in liver and spleen remained constant. Thus, the treated mice had a much larger accumulation and retention of the NP at the target site and a decrease in dose to other organs except spleen. Nanoparticles composed of CdTe, labeled with (125m)Te and capped with ZnS, can be targeted with MAb to sites in the lumen of lung vasculature. In clodronate-treated mice, which have a temporary depletion of phagocytic cells, accumulation in liver was reduced dramatically, whereas that in spleen was not. The targeting to lung was several-fold more efficient in clodronate-treated mice due to larger initial accumulation and better retention of the MAb-targeted NP at that site. This model system indicates that targeting of NP preparations is a competition between the effectiveness of the targeting agent and the natural tendency for RE uptake of the particles. Temporary inhibition of the RE system may enhance the usefulness of NP for drug and radioisotope delivery.
Kennel, Steve J [ORNL; Woodward, Jonathan [ORNL; Rondinone, Adam Justin [ORNL; Wall, Jonathan [ORNL; Mirzadeh, Saed [ORNL
Energy spectrum of charge carriers in Ag{sub 2}Te
Science Conference Proceedings (OSTI)
Conductivity {sigma}(T) and Hall constant R(B, T) are studied for Ag{sub 2}Te with excess 0.1% of Te. The change in the R sign from (-) to (+) is found in dependences R(B) at various temperatures. In the temperature dependences of R in a range of 1-3 kG, two extrema are found, namely, minimum at T {approx} 60 and maximum at T {approx} 80 K, and at B {>=} 5 kG, the double change in sign of R from (-) to (+) and from (+) to (-) is found. Temperatures of sign inversion for R depend on the magnetic field. At B = 15 kG, the sign of R varies from (-) to (+) at T {approx} 38 K, and from (+) to (-) at T {approx} 70 K. It is found approximately in the region of the change in the sign of R(T), the concentration n(T) and electrical conductivity pass through the minimum. It is established that the minima of n(T) and {sigma}(T), extrema in R(T), and sign inversion for R(T) from (-) to (+) as well as the overestimated temperature dependence n{infinity}T{sup 4} are caused by localization of conduction electrons at acceptor levels entering the conduction band of Ag{sub 2}Te. The values of parameters of electrons (n, {mu}{sub n}) and holes (p, {mu}{sub p}) at the points of the change in the sign of R(T) from (-) to (+) and from (+) to (-) are determined.
Aliyev, S. A.; Agayev, Z. F., E-mail: email@example.com; Selimzadeh, R. I. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)
Science Conference Proceedings (OSTI)
The stoichiometric Ga{sub 4}Sb{sub 6}Te{sub 3} and Ga-Sb materials were systematically studied. The alloy Ga{sub 4}Sb{sub 6}Te{sub 3} shows a fast crystallization speed, very high crystallization temperature, T{sub x}, and high electrical contrast. Although stoichiometric GaSb has similar performance and even faster crystallization speed, the electrical contrast is much lower. The other off-stoichiometric compounds we studied all have higher T{sub x} than Ge{sub 2}Sb{sub 2}Te{sub 5} indicating a good amorphous stability. By raising the Sb/Te ratio with GaSb incorporation, T{sub x} and the recrystallization time of melt-quenched, amorphous samples can be effectively increased. The stoichiometric Ga{sub 4}Sb{sub 6}Te{sub 3} with less likelihood of phase-segregation compared to nonstoichiometric compounds is a promising candidate for phase-change memory.
H Cheng; S Raoux; J Jordan-Sweet
Secondary-ion mass spectrometry analysis of the CdS/CdTe interface shows that S diffusion in CdTe increases with substrate temperature and CdCl2 heat treatment. There is also an accumulation of Cl at the interface for CdCl2-treated samples. Modulated photo-reflectance studies shows that devices with CdCl2 heat treatment and open-circuit voltage (Voc) of 835 mV have a distinct high electric-field region in the layer with bandgap of 1.45 eV. Electron-beam induced current measurements reveal a one-sided junction for high Voc devices. The nature of the junction changes with processing. For heterojunction devices, the depletion region includes the highly defective CdS/CdTe interface, which would increase the recombination current and consequently the dark current, leading to lower Voc. In the case of CdCl2-treated cells, the n+-p junction and its high electric-field results in the junction between structurally compatible CdTe and the Te-rich CdSTe alloy, and thus, in higher Voc.
Dhere, R. G.; Zhang, Y.; Romero, M. J.; Asher, S. E.; Young, M.; To, B.; Noufi, R.; Gessert, T. A.
Technical evaluation of Solar Cells, Inc., CdTe modules and array at NREL
The Engineering and Technology Validation Team at the National Renewable Energy Laboratory (NREL) conducts in-situ technical evaluations of polycrystalline thin-film photovoltaic (PV) modules and arrays. This paper focuses on the technical evaluation of Solar Cells, Inc., (SCI) cadmium telluride (CdTe) module and array performance by attempting to correlate individual module and array performance. This is done by examining the performance and stability of the modules and array over a period of more than one year. Temperature coefficients for module and array parameters (P{sub max}V{sub oc}, V{sub max}, I{sub sc}, I{sub max}) are also calculated.
Kroposki, B.; Strand, T.; Hansen, R. [and others
Plasmon-graviton conversion in a magnetic field in TeV-scale gravity
Kaluza-Klein (KK) gravitons emission rates due to plasmon-graviton conversion in magnetic field are computed within the ADD model of TeV-scale gravity. Plasma is described in the kinetic approach as the system of charged particles and Maxwell field both confined on the brane. Interaction with multidimensional gravity living in the bulk with $n$ compact extra dimensions is introduced within the linearized theory. Plasma collective effects enter through the two-point correlation function of the fluctuations of the energy-momentum tensor. The estimate for magnetic stars is presented leading to the lower limit of the D-dimensional Plank mass.
Melkumova, E Yu
Quantum Anomalous Hall Effect in Hg_1-yMn_yTe Quantum Wells
The quantum Hall effect is usually observed when the two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{sub 1-y}Mn{sub y}Te quantum wells, without the external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.
Liu, Chao-Xing; /Tsinghua U., Beijing /Stanford U., Phys. Dept.; Qi, Xiao-Liang; /Stanford U., Phys. Dept.; Dai, Xi; Fang, Zhong; /Beijing, Inst. Phys.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.
Effect of annealing on the electrical properties of thallium-doped PbTe single crystals
Science Conference Proceedings (OSTI)
It is found that electrical parameters of PbTe single crystals, the character of the dependences of these parameters on temperature and Tl impurity concentration, and the conductivity type (signs of {alpha} and R) are governed to a great extent by the temperature of preliminary annealing. The cause of this effect is that the concentration of doubly charged vacancies in the tellurium sublattice increases with an increase in the annealing temperature, as a result of which the formation of electrically neutral or singly charged complexes of impurity-vacancy type becomes more likely.
Ahmedova, G. A., E-mail: email@example.com; Abdinova, G. J.; Abdinov, J. Sh. [National Academy of Sciences of Azerbaijan, Abdullaev Institute of Physics (Azerbaijan)
High-Efficiency CdTe and CIGS Thin-Film Solar Cells: Highlights and Challenges
Science Conference Proceedings (OSTI)
Thin-film photovoltaic (PV) modules of CdTe and Cu(In,Ga)Se{sub 2} (CIGS) have the potential to reach cost-effective PV-generated electricity. These technologies have transitioned from the laboratory to the market place. Pilot production and first-time manufacturing are ramping up to higher capacity and enjoying a flood of venture-capital funding. CIGS solar cells and modules have achieved 19.5% and 13% efficiencies, respectively. Likewise, CdTe cells and modules have reached 16.5% and 10.2% efficiencies, respectively. Even higher efficiencies from the laboratory and from the manufacturing line are only a matter of time. Manufacturing-line yield continues to improve and is surpassing 85%. Long-term stability has been demonstrated for both technologies; however, some failures in the field have also been observed, emphasizing the critical need for understanding degradation mechanisms and packaging options. These two thin-film technologies have a common device/module structure: substrate, base electrode, absorber, junction layer, top electrode, patterning steps for monolithic integration, and encapsulation. The monolithic integration of thin-film solar cells can lead to significant manufacturing cost reduction compared to crystalline Si technology. The CdTe and CIGS modules share common structural elements. In principle, this commonality should lead to similar manufacturing cost per unit area, and thus, the module efficiency becomes the discriminating factor that determines the cost per watt. The long-term potential of the two technologies require R&D emphasis on science and engineering-based challenges to find solutions to achieve targeted cost-effective module performance, and in-field durability. Some of the challenges are common to both, e.g., in-situ process control and diagnostics, thinner absorber, understanding degradation mechanisms, protection from water vapor, and innovation in high-speed processing and module design. Other topics are specific to the technology, such as lower-cost and fast-deposition processes for CIGS, and improved back contact and voltage for CdTe devices.
Noufi, R.; Zweibel, K.
Role of polycrystallinity in CdTe and CuInSe[sub 2] photovoltaic cells
The limiting role of polycrystallinity in thin-film solar calls has been reduced somewhat during the past year, and efficiencies of both CdTe and CuInSe[sub 2] cells are approaching 15%. Quantitative separation of loss mechanisms shows that individual losses, with the exception of forward recombination current, can be made comparable to their single crystal counterparts. One general manifestation of the extraneous trapping states in that the voltage of all polycrystalline thin-film cells drifts upward by 10--50 mV following the onset of illumination.
Sites, J.R. (Colorado State Univ., Fort Collins, CO (United States))
Role of Copper in the Performance of CdS/CdTe Solar Cells: Preprint
The performance of CdS/CdTe solar cells made with evaporated Cu as a primary back contact was studied through current-voltage (JV) at different intensities, quantum efficiency (QE) under light and voltage bias, capacitance-voltage (CV), and drive-level capacitance profiling (DLCP) measurements. The results show that while modest amounts of Cu enhance cell performance, excessive amounts degrade device quality and reduce performance. The analysis is supported with numerical simulations to reproduce and explain some of the experimental results.
Demtsu, S.; Albin, D.; Sites, J.
Role of Copper in the Performance of CdS/CdTe Solar Cells (Poster)
The performance of CdS/CdTe solar cells made with evaporated Cu as a primary back contact was studied through current-voltage (JV) at different intensities, quantum efficiency (QE) under light and voltage bias, capacitance-voltage (CV), and drive-level capacitance profiling (DLCP) measurements. The results show that while modest amounts of Cu enhance cell performance, excessive amounts degrade device quality and reduce performance. The analysis is supported with numerical simulations to reproduce and explain some of the experimental results.
Demtsu, S.; Albin, D.; Sites, J.
Shell model calculation for Te and Sn isotopes in the vicinity of {sup 100}Sn
New Shell Model calculations for even-even isotopes {sup 104-108}Sn and {sup 106,108}Te, in the vicinity of {sup 100}Sn have been performed. The calculations have been carried out using the windows version of NuShell-MSU. The two body matrix elements TBMEs of the effective interaction between valence nucleons are obtained from the renormalized two body effective interaction based on G-matrix derived from the CD-bonn nucleon-nucleon potential. The single particle energies of the proton and neutron valence spaces orbitals are defined from the available spectra of lightest odd isotopes of Sb and Sn respectively.
Yakhelef, A.; Bouldjedri, A. [Physics Department, Farhat abbas University, Setif (Algeria); Physics Department, Hadj Lakhdar University, Batna (Algeria)
Synchrotron X-ray Based Characterization of CdZnTe Crystals
Science Conference Proceedings (OSTI)
Synthetic CdZnTe (CZT) crystals can be used for the room temperature-based detection of gamma radiation. Structural/morphological heterogeneities within CZT, such as secondary phases (namely, precipitates and inclusions), can negatively affect detector performance. We used a synchrotron-based x-ray technique, specifically extended x-ray absorption fine-structure (EXAFS) spectroscopy, to determine whether there are differences on a local structural level between intact CZT of high and low radiation detector performance. These studies were complemented by data on radiation detector performance and transmission infrared (IR) imaging. The EXAFS studies revealed no detectable local structural differences between the two types of CZT materials.
Duff,M.; Hunter, D.; Nuessle, P.; Black, D.; Burdette, H.; Woicik, J.; Burger, A.; Groza, M.
Unconventional fermions: The Price of Quark-Lepton Unification at TeV Scales
The early petite unification (PUT) of quarks and leptons at TeV scales with sin^2 theta_W(M^2_Z) used as a constraint, necessitates the introduction of extra quarks and leptons with unconventional electric charges (up to 4/3 for the quarks and 2 for the leptons). This talk, in honor of Paul Frampton's 60th birthday, will be devoted to the motivation and construction of models of early unification and to their implications, including the issues of rare decays and unconventional fermions.
P. Q. Hung
Effect of Sub-Bandgap Illumination on the Internal Electric Field of CdZnTe
Post-growth manipulation of the internal electric field in CdZnTe crystals using sub-bandgap illumination is measured as a function of temperature through infrared (IR) transmission measurements. Using near sub-bandgap IR illumination, both the optical de-trapping of charge carriers and the reduction in carrier recombination increased the mobility lifetime in the crystal. The increased carrier transport is a direct result of decreased hole and electron trapping in addition to other underlying mechanisms. Concentration of the electric field near the cathode is also observed. We measured the electric field distribution with sub-bandgap illumination as a function of temperature via the Pockels effect.
Washington, A.
Flexible Micro Thermoelectric Generator based on Electroplated Bi2Te3
We present and discuss the fabrication process and the performance of a flexible micro thermoelectric generator with electroplated Bi2Te3 thermocouples in a SU-8 mold. Demonstrator devices generate 278uWcm-2 at dTmeas=40K across the experimental set up. Based on model calculations, a temperature difference of dTG=21.4K across the generator is assumed. Due to the flexible design and the chosen generator materials, the performance stays high even for curved contact surfaces. The measurement results correlate well with the model based design optimization predictions.
Schwyter, E; Durrer, L; Hierold, Ch
Size-Dependent Polar Ordering on Colloidal GeTe Nanocrystals
The question of the nature and stability of polar ordering in nanoscale ferroelectrics is examined with colloidal nanocrystals of germanium telluride (GeTe). We provide atomic-scale evidence for room-temperature polar ordering in individual nanocrystals using aberration-corrected transmission electron microscopy and demonstrate a reversible, size-dependent polar-nonpolar phase transition of displacive character in nanocrystal ensembles. A substantial linear component of the distortion is observed, which is in contrast with theoretical reports predicting a toroidal state.
M Polking; J Urban; D Milliron; H Zheng; E Chan; M Caldwell; S Raoux; C Kisielowski; J Ager; et al.
Scrutinizing the ZW+W- vertex at the Large Hadron Collider at 7 TeV
We analyze the potential of the CERN Large Hadron Collider running at 7 TeV to search for deviations from the Standard Model predictions for the triple gauge boson coupling ZW+W- assuming an integrated luminosity of 1 fb^{-1}. We show that the study of W+W- and W^\\pm Z productions, followed by the leptonic decay of the weak gauge bosons can improve the present sensitivity on the anomalous couplings \\Delta g_1^Z, \\Delta \\kappa_Z, \\lambda_Z, g_4^Z, and \\tilde{\\lambda}_Z at the 2\\sigma level.
O. J. P. Eboli; J. Gonzalez-Fraile; M. C. Gonzalez-Garcia
TeV Scale Quantum Gravity and Mirror Supernovae as Sources of Gamma Ray Bursts
Mirror matter models have been suggested recently as an explanation of neutrino puzzles and microlensing anomalies. We show that mirror supernovae can be a copious source of energetic gamma rays if one assumes that the quantum gravity scale is in the TeV range. We show that under certain assumptions plausible in the mirror models, the gamma energies could be degraded to the 10 MeV range (and perhaps even further) so as to provide an explanation of observed gamma ray bursts. This mechanism for the origin of the gamma ray bursts has the advantage that it neatly avoids the ``baryon load problem''.
R. N. Mohapatra; S. Nussinov; V. L. Teplitz
Hidden from View: Neutrino Masses, Dark Matter and TeV-Scale Leptogenesis in a Neutrinophilic 2HDM
We consider a simple extension of the Standard Model providing dark matter and a TeV-scale seesaw mechanism that also allows for viable leptogenesis. In addition to the Standard Model degrees of freedom, the model contains a neutrinophilic Higgs doublet, a scalar singlet, and six singlet fermions (including three right-handed Majorana neutrinos) that are charged under a local $U(1)^\\prime$ gauge symmetry. We show how the $U(1)^\\prime$ charge assignments and the choice of scalar potential can lead to a TeV-scale seesaw mechanism and $\\mathcal{O}(1)$ neutrino Yukawa couplings in a straightforward way. While this scenario has all the ingredients one would expect for significant experimental signatures, including several new TeV scale degrees of freedom, we find that most distinctive features associated with neutrino mass generation, leptogenesis and the dark sector are likely to remain inaccessible in the absence of additional lepton flavor symmetries.
Wei Chao; Michael J. Ramsey-Musolf
Science Conference Proceedings (OSTI)
The purpose of the Guideline to Good Practices for Control and Calibration of Measuring and Test Equipment (M TE) at DOE Nuclear Facilities is to provide contractor maintenance organizations with information that may be used for the development and implementation of a rigorously controlled maintenance program directed at controlling and calibrating M TE used for maintenance tasks at DOE nuclear facilities. This document is intended to be an example guideline for the implementation of DOE Order 4330.4A, Maintenance Management Program, Chapter II, Element 11. DOE contractors should not feel obligated to adopt all parts of this guide. Rather, they should use the information contained herein as a guide for developing an M TE program applicable to their facility.
Not Available
Reduction of surface leakage current by surface passivation of Cd.sub.1-x Zn.sub.x Te and other materials using hyperthermal oxygen atoms. Surface effects are important in the performance of CdZnTe room-temperature radiation detectors used as spectrometers since the dark current is often dominated by surface leakage. A process using high-kinetic-energy, neutral oxygen atoms (.about.3 eV) to treat the surface of CdZnTe detectors at or near ambient temperatures is described. Improvements in detector performance include significantly reduced leakage current which results in lower detector noise and greater energy resolution for radiation measurements of gamma- and X-rays, thereby increasing the accuracy and sensitivity of measurements of radionuclides having complex gamma-ray spectra, including special nuclear materials.
Hoffbauer, Mark A. (Los Alamos, NM); Prettyman, Thomas H. (Los Alamos, NM)
{gamma}-ray spectroscopy of neutron-deficient {sup 110}Te. I. Low- and intermediate-spin structures
Excited states have been populated in {sub 52}{sup 110}Te via the {sup 58}Ni({sup 58}Ni,{alpha}2p{gamma}) reaction at 250 MeV. The Gammasphere {gamma}-ray spectrometer was augmented with ancillary detectors for charged-particle and neutron detection in order to provide clean channel selection. The known level scheme of {sup 110}Te has been greatly expanded with the addition of many new structures. Above spin 8{sup +}, negative-parity structures become yrast. The level scheme of {sup 110}Te below 30({Dirac_h}/2{pi}) is discussed in this paper, including possible evidence for octupole correlations inferred from strong B(E1) strengths.
Paul, E. S.; Boston, A. J.; Nolan, P. J.; Semple, A. T. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Chiara, C. J.; Fossan, D. B.; Lane, G. J.; Sears, J. M.; Starosta, K. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Devlin, M.; LaFosse, D. R.; Sarantites, D. G. [Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States); Freeman, S. J.; Leddy, M. J. [Schuster Laboratory, University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Lee, I. Y.; Macchiavelli, A. O. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Smith, J. F. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Schuster Laboratory, University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)
TeV Burst of Gamma-Ray Bursts and Ultra High Energy Cosmic Rays
Some recent experiments detecting very high energy (VHE) gamma-rays above 10-20 TeV independently reported VHE bursts for some of bright gamma-ray bursts (GRBs). If these signals are truly from GRBs, these GRBs must emit a much larger amount of energy as VHE gamma-rays than in the ordinary photon energy range of GRBs (keV-MeV). We show that such extreme phenomena can be reasonably explained by synchrotron radiation of protons accelerated to \\sim 10^{20-21} eV, which has been predicted by Totani (1998a). Protons seem to carry about (m_p/m_e) times larger energy than electrons, and hence the total energy liberated by one GRB becomes as large as \\sim 10^{56} (\\Delta \\Omega / 4 \\pi) ergs. Therefore a strong beaming of GRB emission is highly likely. Extension of the VHE spectrum beyond 20 TeV gives a nearly model-independent lower limit of the Lorentz factor of GRBs, as $\\gamma \\gtilde 500$. Furthermore, our model gives the correct energy range and time variability of ordinary keV-MeV gamma-rays of GRBs by synchrotron radiation of electrons. Therefore the VHE bursts of GRBs strongly support the hypothesis that ultra high energy cosmic rays observed on the Earth are produced by GRBs.
Tomonori Totani
Charge transport properties in CdZnTe detectors grown by the vertical Bridgman technique
Science Conference Proceedings (OSTI)
Presently, a great amount of effort is being devoted to the development of CdTe and CdZnTe (CZT) detectors for a large variety of applications such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). In this technique, the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible, thereby allowing larger single grains with a lower dislocation density to be obtained. Several mono-electrode detectors were realized, with each having two planar gold contacts. The samples are characterized by an active area of about 7 mm x 7 mm and thicknesses ranging from 1 to 2 mm. The charge transport properties of the detectors have been studied by mobility-lifetime ({mu} x {tau}) product measurements, carried out at the European Synchrotron Radiation Facility (Grenoble, France) in the planar transverse field configuration, where the impinging beam direction is orthogonal to the collecting electric field. We have performed several fine scans between the electrodes with a beam spot of 10 {mu}m x 10 {mu}m at various energies from 60 to 400 keV. In this work, we present the test results in terms of the ({mu} x {tau}) product of both charge carriers.
Auricchio, N.; Caroli, E. [INAF/IASF-Bologna, Bologna, 40129 (Italy); Marchini, L.; Zappettini, A. [IMEM-CNR, Parma, 43100 (Italy); Abbene, L. [DIFI, University of Palermo, Palermo, 90128 (Italy); Honkimaki, V. [European Synchrotron Radiation Facility, Grenoble, 38000 (France)
Recent results with a CdTe imaging portal scanner for radiation therapy
One of the most promising means for improving the quality of radiation therapy is the use of real-time imaging systems for routine portal position verification. The authors have constructed a prototype portal imager using a linear array of 256 CdTe photovoltaic detectors, each 2X2X2 mm. The array is attached to a compact linear scanner which is to be mounted in a cassette shaped package located below the patient table. The array of detectors is moved under the patient during image acquisition. The high stopping power of the CdTe allows a high contrast image to be made using a single linac pulse for each array position. In tests conducted with a 4 MV linac, this system produced 50 cm x 35 cm images with an open field signal-to-noise ratio of 143 and 2 mm spatial resolution in less than 3 seconds. This corresponds to a signal-to-noise ratio of 1 for 1% contrast objects. Ultimately, a signal-to-noise ratio greater than 5 at 1% contrast should be achievable with no loss of spatial resolution or increase in acquisition time.
Entine, G.; Redus, R.H.; Feyder, A. (Radiation Monitoring Devices, Inc., Watertown, MA (United States)); Biggs, P.J. (Massachusetts General Hospital, Boston, MA (United States))
Cosmic ray knee and new physics at the TeV scale
We analyze the possibility that the cosmic ray knee appears at an energy threshold where the proton-dark matter cross section becomes large due to new TeV physics. It has been shown that such interactions could break the proton and produce a diffuse gamma ray flux consistent with MILAGRO observations. We argue that this hypothesis implies knees that scale with the atomic mass for the different nuclei, as KASKADE data seem to indicate. We find that to explain the change in the spectral index in the flux from E^{-2.7} to E^{-3.1} the cross section must grow like E^{0.4+\\beta} above the knee, where \\beta=0.3-0.6 parametrizes the energy dependence of the age (\\tau \\propto E^{-\\beta}) of the cosmic rays reaching the Earth. The hypothesis also requires mbarn cross sections (that could be modelled with TeV gravity) and large densities of dark matter (that could be clumped around the sources of cosmic rays). We argue that neutrinos would also exhibit a threshold at E=(m_\\chi/m_p)E_{knee}\\approx 10^8 GeV where their interaction with a nucleon becomes strong. Therefore, the observation at ICECUBE or ANITA of standard neutrino events above this threshold would disprove the scenario.
Roberto Barcelo; Manuel Masip; Iacopo Mastromatteo
Cosmic ray knee and new physics at the TeV scale
We analyze the possibility that the cosmic ray knee appears at an energy threshold where the proton-dark matter cross section becomes large due to new TeV physics. It has been shown that such interactions could break the proton and produce a diffuse gamma ray flux consistent with MILAGRO observations. We argue that this hypothesis implies knees that scale with the atomic mass for the different nuclei, as KASKADE data seem to indicate. We find that to explain the change in the spectral index in the flux from E^{-2.7} to E^{-3.1} the cross section must grow like E^{0.4+\\beta} above the knee, where \\beta=0.3-0.6 parametrizes the energy dependence of the age (\\tau \\propto E^{-\\beta}) of the cosmic rays reaching the Earth. The hypothesis also requires mbarn cross sections (that could be modelled with TeV gravity) and large dark matter densities in the galactic disc (that might be accommodated in a two-component model). We argue that neutrinos would also exhibit a threshold at E=(m_\\chi/m_p)E_{knee}\\approx 10^8 GeV...
Barcelo, Roberto; Mastromatteo, Iacopo
SHI induced enhancement in conductivity of PbTe thin film for thermoelectric applications
PbTe thin film were synthesized using thermal evaporation and irradiated by 100 MeV Ag ions at different fluences ranging from 3x10{sup 13} and 1x10{sup 14} ions/cm{sup 2}. Pristine films annealed under Ar atm at 250 deg. C for 1 hr. X-ray Diffraction (XRD) of pristine and irradiated films reveals the improvement of PbTe phase with increasing fluence. The thickness of the film is decreased from 195 nm to 150 nm after ion irradiation as indicated by Rutherford backscattering spectrometry (RBS) analysis due to the sputtering. Resistivity measurement using four probe techniques of these films shows the conductivity enhancement with ion fluence. The conductivity is found to be {approx} 6 fold at fluence 3x10{sup 13} ions/cm{sup 2} whereas it decreases to 3 fold after annealing in comparison to pristine sample. On further increasing the fluence from 3x10{sup 13} ions/cm{sup 2}, the properties of the film begin to deteriorate. SHI induced modification may be explained on the basis of oxygen desorption and change in stochiometry of film during irradiation.
Gupta, Srashti; Agarwal, D. C.; Singh, J. P.; Tripathi, S. K.; Neeleshwar, S.; Asokan, K.; Panigrahi, B. K.; Avasthi, D. K. [University School of Basic and Applied Sciences, GGS Indraprastha University, Dwarka, Delhi 110075 (India); Inter University Accelerator Centre, New Delhi-110067 (India); Department of Physics, Panjab University, Chandigarh-160 014 (India); University School of Basic and Applied Sciences, GGS Indraprastha University, Dwarka, Delhi 110075 (India); Inter University Accelerator Centre, New Delhi-110067 (India); Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Inter University Accelerator Centre, New Delhi-110067 (India)
Measurements of the Cerenkov light emitted by a TeO2 crystal
Bolometers have proven to be good instruments to search for rare processes because of their excellent energy resolution and their extremely low intrinsic background. In this kind of detectors, the capability of discriminating alpha particles from electrons represents an important aspect for the background reduction. One possibility for obtaining such a discrimination is provided by the detection of the Cerenkov light which, at the low energies of the natural radioactivity, is only emitted by electrons. In this paper, the results of the analysis of the light emitted by a TeO2 crystal at room temperature when transversed by a cosmic ray are reported. Light is promptly emitted after the particle crossing and a clear evidence of its directionality is also found. These results represent a strong indication that Cerenkov light is the main, if not even the only, component of the light signal in a TeO2 crystal. They open the possibility to make large improvements in the performance of experiments based on this kind of materials
F. Bellini; N. Casali; I. Dafinei; M. Marafini; S. Morganti; F. Orio; D. Pinci; M. Vignati; C. Voena
Improved Intrinsic Stability of CdTe Polycrystalline Thin Film Devices
A systems-driven approach linking upstream solar cell device fabrication history with downstream performance and stability has been applied to CdS/CdTe small-area device research. The best resulting initial performance (using thinner CdS, thicker CdTe, no oxygen during VCC, and the use of NP etch) was shown to simultaneously correlate with poor stability. Increasing the CdS layer thickness significantly improved stability at only a slight decrease in overall performance. It was also determined that cell perimeter effects can accelerate degradation in these devices. A ''margined'' contact significantly reduces the contribution of edge shunting to degradation, and thus yields a more accurate determination of the intrinsic stability. Pspice discrete element models demonstrate how spatially localized defects can effectively dominate degradation. Mitigation of extrinsic shunting improved stabilized efficiency degradation levels (SEDL) to near 20% in 100 C tests. Further process optimization to reduce intrinsic effects improved SEDL to better than 10% at the same stress temperatures and times.
Albin, D.; Berniard, T.; McMahon, T.; Noufi, R.; Demtsu, S.
High-spin structures of 124-131Te: Competition of proton and neutron pair breakings
The 124-131Te nuclei have been produced as fission fragments in two fusion reactions induced by heavy-ions (12C + 238U at 90 MeV bombarding energy and 18O + 208Pb at 85 MeV) and studied with the Euroball array. Their high-spin level schemes have been extended to higher excitation energy from the triple gamma-ray coincidence data. The gamma-gamma angular correlations have been analyzed in order to assign spin and parity values to many observed states. Moreover the half-lives of isomeric states have been measured from the delayed coincidences between the fission-fragment detector SAPhIR and Euroball, as well as from the timing information of the Ge detectors. The behaviors of the yrast structures identified in the present work are first discussed in comparison with the general features known in the mass region, particularly the breakings of neutron pairs occupying the nuh11/2 orbit identified in the neighboring Sn nuclei. The experimental level schemes are then compared to shell-model calculations performed in this work. The analysis of the wave functions shows the effects of the proton-pair breaking along the yrast lines of the heavy Te isotopes.
A. Astier; M. -G. Porquet; Ts. Venkova; Ch. Theisen; G. Duchene; F. Azaiez; G. Barreau; D. Curien; I. Deloncle; O. Dorvaux; B. J. P. Gall; M. Houry; R. Lucas; N. Redon; M. Rousseau; O. Stezowski
Innovative sputtering techniques for CIS and CdTe submodule fabrication
This report describes work done during Phase 1 of the subject subcontract. The subcontract was designed to study innovative deposition techniques, such as the rotating cylindrical magnetron sputtering system and electrodeposition for large-area, low-cost copper indium diselenide (CIS) and cadmium telluride (CdTe) devices. A key issue for photovoltaics (PV) in terrestrial and future space applications is producibility, particularly for applications using a large quantity of PV. Among the concerns for fabrication of polycrystalline thin-film PV, such as CIS and CdTe, are production volume, cost, and minimization of waste. Both rotating cylindrical magnetron (C-Mag[trademark]) sputtering and electrodeposition have tremendous potential for the fabrication of polycrystalline thin-film PV due to scaleability, efficient utilization of source materials, and inherently higher deposition rates. In the case of sputtering, the unique geometry of the C-Mae facilitates innovative cosputtering and reactive sputtering that could lead to greater throughput reduced health and safety risks, and, ultimately, lower fabrication cost. Electrodeposited films appear to be adherent and comparable with low-cost fabrication techniques. Phase I involved the initial film and device fabrication using the two techniques mentioned herein. Devices were tested by both internal facilities, as well as NREL and ISET.
Armstrong, J.M.; Misra, M.S.; Lanning, B. (Martin Marietta Aerospace, Denver, CO (United States). Astronautics Group)
CANGAROO-III OBSERVATION OF TeV GAMMA RAYS FROM THE VICINITY OF PSR B1706-44
Science Conference Proceedings (OSTI)
Observation by the CANGAROO-III stereoscopic system of the Imaging Cherenkov Telescope has detected extended emission of TeV gamma rays in the vicinity of the pulsar PSR B1706-44. The strength of the signal observed as gamma-ray-like events varies when we apply different ways of emulating background events. The reason for such uncertainties is argued in relevance to gamma rays embedded in the 'OFF-source data', that is, unknown sources and diffuse emission in the Galactic plane, namely, the existence of a complex structure of TeV gamma-ray emission around PSR B1706-44.
Enomoto, R.; Kifune, T. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Kushida, J.; Hattori, T.; Ishioka, H.; Kawachi, A. [Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292 (Japan); Nakamori, T. [Department of Basic Physics, Tokyo Institute of Technology, Meguro, Tokyo, 152-8551 (Japan); Bicknell, G. V. [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia); Clay, R. W. [School of Chemistry and Physics, University of Adelaide, SA 5005 (Australia); Edwards, P. G. [Narrabri Observatory of the Australia Telescope National Facility, CSIRO, Epping, NSW 2121 (Australia); Gunji, S.; Inoue, K. [Department of Physics, Yamagata University, Yamagata 990-8560 (Japan); Hara, S. [Ibaraki Prefectural University of Health Sciences, Ami, Ibaraki 300-0394 (Japan); Hara, T. [Faculty of Management Information, Yamanashi Gakuin University, Kofu, Yamanashi 400-8575 (Japan); Hayashi, S.; Kajino, F. [Department of Physics, Konan University, Kobe, Hyogo 658-8501 (Japan); Higashi, Y.; Kabuki, S. [Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Hirai, Y. [Faculty of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Katagiri, H. [Department of Physical Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)
Crystal Defects in CdZnTe Crystals Grown by the Modified Low-Pressure Bridgman Method
Science Conference Proceedings (OSTI)
Cadmium Zinc Telluride (CZT) is among the most promising materials for room-temperature X- and gamma-ray detectors. However, crystal defects such as Te inclusions and subgrain boundaries significantly hamper their performances. In this work, we evaluated CZT crystals grown by the modified low-pressure Bridgman technique at the IMEM Institute, Parma. We characterized the crystals by IR microscopy to identify the sizes and concentrations of the Te inclusions, along with high spatial resolution X-ray response mapping to measure the uniformity of their charge-transport properties. In addition, we employed white X-ray beam diffraction topography to analyze their crystalline structure.
Bolotnikov A.; Marchini, L.; Zappettini, M.; Zha, M.; Zambelli, N.; Camarda, G.S.; James, R.B.
Science Conference Proceedings (OSTI)
Purpose: In radiation therapy treatments the standard approach of taking a planar portal or CIAO image offers setup verifications crucial to accurate radiation delivery. A substantial detector thickness necessary for MV photon absorption is a limitation due to large signal spreading; the requirements of large areas (up to 40�40 cm) and commercial viability dictate the use of non?crystalline semiconductors. We propose a detector based on thin?film CdTe technologies recently developed for photovoltaic applications. It utilizes a stack of CdTe photovoltaic layers
Nanocrystalline Bi{sub 2}Te{sub 3} was produced by mechanical alloying and its properties were investigated by differential scanning calorimetry (DSC) x-ray diffraction (XRD), Raman spectroscopy (RS), and photoacoustic spectroscopy (PAS). Combining the XRD and RS results, the volume fraction of the interfacial component in as-milled and annealed samples was estimated. The PAS results suggest that the contribution of the interfacial component to the thermal diffusivity of nanostructured Bi{sub 2}Te{sub 3} is very significant.
Souza, S. M.; Triches, D. M.; Poffo, C. M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, C.P. 476, Florianopolis, Santa Catarina 88040-900 (Brazil); Lima, J. C. de; Grandi, T. A. [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, Florianopolis, Santa Catarina 88040-900 (Brazil); Biasi, R. S. de [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro-RJ (Brazil)
RECYCLING OF CdTe PHOTOVOLTAIC MODULES: RECOVERY OF CADMIUM AND TELLURIUM Vasilis Fthenakis1, Paul the recovery of tellurium. Keywords: Photovoltaic, Recycling, CdTe 1. INTRODUCTION Photovoltaic modules on a larger scale cell (i.e., 5 L) which prod
Electrical properties of the Cd{sub 1-x}Mg{sub x} Te alloys of various composition (0.1 {<=} x {<=} 0.3) are studied. It is established that at x = 0.1, a low-resistivity p-type material with parameters close to undoped CdTe is formed. A feature of the Cd{sub 0.9}Mg{sub 0.1} Te crystals is that, during deposition of Cu on their surface from a saturated CuSO{sub 4} solution, ohmic contact is formed, the characteristics of which do not worsen in a wide temperature range (80-300 K). The study of characteristics with and without illumination of the Cu/p-Cd{sub 0.9}Mg{sub 0.1}Te/n-Cd{sub 0.9}Mg{sub 0.1}Te/In structures have shown that they are promising as photoconverters of solar radiation.
Parfenyuk, O. A., E-mail: email@example.com; Ilashchuk, M. I.; Ulyanitsky, K. S. [Fed'kovich National University (Ukraine)
LOWER LIMITS ON ULTRAHIGH-ENERGY COSMIC RAY AND JET POWERS OF TeV BLAZARS
Science Conference Proceedings (OSTI)
Lower limits on the power emitted in ultrahigh-energy cosmic rays (UHECRs), which are assumed to be protons with energy {approx}> 10{sup 17}-10{sup 20} eV, are derived for TeV blazars with the assumption that the observed TeV {gamma}-rays are generated due to interactions of these protons with cosmic microwave photons. The limits depend on the spectrum of the injected UHECR protons. While for a -2.2 injection spectrum the lower limits on the powers emitted in UHECRs by 1ES 0229+200, 1ES 1101-232, and 1ES 0347-121 are lower than their respective synchrotron luminosities ({approx}10{sup 46} erg s{sup -1}), in the case of 1ES 1426+428 it exceeds the corresponding synchrotron luminosity by up to an order of magnitude. The proposed Auger North Observatory should be able to detect 4 Multiplication-Sign 10{sup 19} eV cosmic-ray (CR) protons from 1ES 1426+428 within a few years of operation and test the TeV {gamma}-ray production model by UHECR energy losses while propagating along the line of sight or constrain the intergalactic magnetic field to be larger than {approx}10{sup -16} G in case of no detection. The lower limits on the apparent-isotropic jet power from accelerated 10{sup 10}-10{sup 20} eV proton spectra in the blazar jet is of the order of the Eddington luminosity of a 10{sup 9} M{sub Sun} black hole for a CR injection spectrum -2.2 or harder for all blazars considered except for 1ES 1426+428. In the case of the latter, the apparent-isotropic jet power exceeds the Eddington luminosity by an order of magnitude. For an injection spectrum softer than -2.2, as is required to fit the observed CR data above {approx}10{sup 17}-10{sup 18} eV, the Eddington luminosity is exceeded by the lower limits on the jet power for all blazars considered.
Razzaque, Soebur [School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030 (United States); Dermer, Charles D.; Finke, Justin D., E-mail: firstname.lastname@example.com [Space Science Division, US Naval Research Laboratory, Washington, DC 20375 (United States)
Effect of Al(OH)3 on the hydrogen generation of aluminumewater system Hsin-Te Teng a
Effect of Al(OH)3 on the hydrogen generation of aluminumewater system Hsin-Te Teng a , To-Ying Lee effect of Al(OH)3 powders on Al/H2O system for hydrogen generation was demonstrated. crystalline Al(OH)3 powder acts an effective additive to the Al/H2O system.
Cao, Guozhong
Observation of an Anisotropy in the Galactic Cosmic Ray arrival direction at 400 TeV with IceCube
In this paper we report the first observation in the Southern hemisphere of an energy dependence in the Galactic cosmic ray anisotropy up to a few hundred TeV. This measurement was performed using cosmic ray induced muons recorded by the partially deployed IceCube observatory between May 2009 and May 2010. The data include a total of 33$\\times 10^{9}$ muon events with a median angular resolution of $\\sim3^{\\circ}$ degrees. A sky map of the relative intensity in arrival direction over the Southern celestial sky is presented for cosmic ray median energies of 20 and 400 TeV. The same large-scale anisotropy observed at median energies around 20 TeV is not present at 400 TeV. Instead, the high energy skymap shows a different anisotropy structure including a deficit with a post-trial significance of -6.3$\\sigma$. This anisotropy reveals a new feature of the Galactic cosmic ray distribution, which must be incorporated into theories of the origin and propagation of cosmic rays.
IceCube Collaboration; R. Abbasi; Y. Abdou; T. Abu-Zayyad; M. Ackermann; J. Adams; J. A. Aguilar; M. Ahlers; M. M. Allen; D. Altmann; K. Andeen; J. Auffenberg; X. Bai; M. Baker; S. W. Barwick; R. Bay; J. L. Bazo Alba; K. Beattie; J. J. Beatty; S. Bechet; J. K. Becker; K. -H. Becker; M. L. Benabderrahmane; S. BenZvi; J. Berdermann; P. Berghaus; D. Berley; E. Bernardini; D. Bertrand; D. Z. Besson; D. Bindig; M. Bissok; E. Blaufuss; J. Blumenthal; D. J. Boersma; C. Bohm; D. Bose; S. B�ser; O. Botner; A. M. Brown; S. Buitink; K. S. Caballero-Mora; M. Carson; D. Chirkin; B. Christy; F. Clevermann; S. Cohen; C. Colnard; D. F. Cowen; A. H. Cruz Silva; M. V. D'Agostino; M. Danninger; J. Daughhetee; J. C. Davis; C. De Clercq; T. Degner; L. Demir�rs; F. Descamps; P. Desiati; G. de Vries-Uiterweerd; T. DeYoung; J. C. D�az-V�lez; M. Dierckxsens; J. Dreyer; J. P. Dumm; M. Dunkman; J. Eisch; R. W. Ellsworth; O. Engdeg�rd; S. Euler; P. A. Evenson; O. Fadiran; A. R. Fazely; A. Fedynitch; J. Feintzeig; T. Feusels; K. Filimonov; C. Finley; T. Fischer-Wasels; B. D. Fox; A. Franckowiak; R. Franke; T. K. Gaisser; J. Gallagher; L. Gerhardt; L. Gladstone; T. Gl�senkamp; A. Goldschmidt; J. A. Goodman; D. G�ra; D. Grant; T. Griesel; A. Gro�; S. Grullon; M. Gurtner; C. Ha; A. Haj Ismail; A. Hallgren; F. Halzen; K. Han; K. Hanson; D. Heinen; K. Helbing; R. Hellauer; S. Hickford; G. C. Hill; K. D. Hoffman; B. Hoffmann; A. Homeier; K. Hoshina; W. Huelsnitz; J. -P. H�l�; P. O. Hulth; K. Hultqvist; S. Hussain; A. Ishihara; E. Jacobi; J. Jacobsen; G. S. Japaridze; H. Johansson; K. -H. Kampert; A. Kappes; T. Karg; A. Karle; P. Kenny; J. Kiryluk; F. Kislat; S. R. Klein; J. -H. K�hne; G. Kohnen; H. Kolanoski; L. K�pke; S. Kopper; D. J. Koskinen; M. Kowalski; T. Kowarik; M. Krasberg; G. Kroll; N. Kurahashi; T. Kuwabara; M. Labare; K. Laihem; H. Landsman; M. J. Larson; R. Lauer; J. L�nemann; J. Madsen; A. Marotta; R. Maruyama; K. Mase; H. S. Matis; K. Meagher; M. Merck; P. M�sz�ros; T. Meures; S. Miarecki; E. Middell; N. Milke; J. Miller; T. Montaruli; R. Morse; S. M. Movit; R. Nahnhauer; J. W. Nam; U. Naumann; D. R. Nygren; S. Odrowski; A. Olivas; M. Olivo; A. O'Murchadha; S. Panknin; L. Paul; C. P�rez de los Heros; J. Petrovic; A. Piegsa; D. Pieloth; R. Porrata; J. Posselt; C. C. Price; P. B. Price; G. T. Przybylski; K. Rawlins; P. Redl; E. Resconi; W. Rhode; M. Ribordy; M. Richman; J. P. Rodrigues; F. Rothmaier; C. Rott; T. Ruhe; D. Rutledge; B. Ruzybayev; D. Ryckbosch; H. -G. Sander; M. Santander; S. Sarkar; K. Schatto; T. Schmidt; A. Sch�nwald; A. Schukraft; A. Schultes; O. Schulz; M. Schunck; D. Seckel; B. Semburg; S. H. Seo; Y. Sestayo; S. Seunarine; A. Silvestri; G. M. Spiczak; C. Spiering; M. Stamatikos; T. Stanev; T. Stezelberger; R. G. Stokstad; A. St��l; E. A. Strahler; R. Str�m; M. St�er; G. W. Sullivan; Q. Swillens; H. Taavola; I. Taboada; A. Tamburro; A. Tepe; S. Ter-Antonyan; S. Tilav; P. A. Toale; S. Toscano; D. Tosi; N. van Eijndhoven; J. Vandenbroucke; A. Van Overloop; J. van Santen; M. Vehring; M. Voge; C. Walck; T. Waldenmaier; M. Wallraff; M. Walter; Ch. Weaver; C. Wendt; S. Westerhoff; N. Whitehorn; K. Wiebe; C. H. Wiebusch; D. R. Williams; R. Wischnewski; H. Wissing; M. Wolf; T. R. Wood; K. Woschnagg; C. Xu; D. L. Xu; X. W. Xu; J. P. Yanez; G. Yodh; S. Yoshida; P. Zarzhitsky; M. Zoll
The ATLAS experiment has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at ?s=7??TeV. The full data set acquired in 2010 is used, corresponding to ...
Taylor, Frank E.
Inclusive jet and dijet cross sections have been measured in proton-proton collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the Large Hadron Collider. The cross sections were measured using jets ...
Taylor, Frank E.
Synchrotron radiation x-ray absorption fine-structure and Raman studies on CdZnTe ternary alloys
The synchrotron radiation (SR) X-ray absorption fine-structure spectroscopy (XAFS) technology has been employed to obtained Zn K-edge absorption spectra for Cd1[subscript 1-x]Zn[subscript x]Te alloy with x = 0.03, 0.10, ...
Becla, Piotr
Recent claims that the strength B{sub IGMF} of the intergalactic magnetic field (IGMF) is {approx}> 10{sup -15} G are based on upper limits to the expected cascade flux in the GeV band produced by blazar TeV photons absorbed by the extragalactic background light. This limit depends on an assumption that the mean blazar TeV flux remains constant on timescales {approx}> 2(B{sub IGMF}/10{sup -18}G){sup 2}/(E/10 GeV){sup 2} yr for an IGMF coherence length {approx}1 Mpc, where E is the measured photon energy. Restricting TeV activity of 1ES 0229+200 to {approx}3-4 years during which the source has been observed leads to a more robust lower limit of B{sub IGMF} {approx}> 10{sup -18} G, which can be larger by an order of magnitude if the intrinsic source flux above {approx}5-10 TeV from 1ES 0229+200 is strong.
Dermer, Charles D.; Razzaque, Soebur; Finke, Justin D. [Space Science Division, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Cavadini, Massimo [Dipartimento di Fisica e Matematica, Universita dell'Insubria, via Valleggio 11, 22100, Como (Italy); Chiang, James [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Lott, Benoit, E-mail: firstname.lastname@example.com [CNRS/IN2P3, Centre d' Etudes Nucleaires Bordeaux Gradignan, UMR 5797, Gradignan, 33175 (France)
A measurement of the 2 neutrino double beta decay rate of Te-130 in the CUORICINO experiment
Science Conference Proceedings (OSTI)
CUORICINO was a cryogenic bolometer experiment designed to search for neutrinoless double beta decay and other rare processes, including double beta decay with two neutrinos (2{nu}{beta}{beta}). The experiment was located at Laboratori Nazionali del Gran Sasso and ran for a period of about 5 years, from 2003 to 2008. The detector consisted of an array of 62 TeO{sub 2} crystals arranged in a tower and operated at a temperature of #24;10 mK. Events depositing energy in the detectors, such as radioactive decays or impinging particles, produced thermal pulses in the crystals which were read out using sensitive thermistors. The experiment included 4 enriched crystals, 2 enriched with {sup 130}Te and 2 with {sup 128}Te, in order to aid in the measurement of the 2{nu}{beta}{beta} rate. The enriched crystals contained a total of #24;350 g {sup 130}Te. The 128-enriched (130-depleted) crystals were used as background monitors, so that the shared backgrounds could be subtracted from the energy spectrum of the 130- enriched crystals. Residual backgrounds in the subtracted spectrum were fit using spectra generated by Monte-Carlo simulations of natural radioactive contaminants located in and on the crystals. The 2{nu}{beta}{beta} half-life was measured to be T{sup 2{nu}}{sub 1/2} = [9.81{+-} #6;0.96(stat){+-} 0.49(syst)]#2;x10{sup 20} y.
Kogler, Laura
Study of Baryonic R-Parity Violating MSSM Using Jet Substructure Technique at the 14 TeV LHC
We study the discovery reach of the gluino ($\\widetilde{g}$) and the lightest stop squark ($\\widetilde{t}_1$) with baryonic R-parity violation (UDD type) in the context of Minimal Supersymmetric Standard Model (MSSM) at the 14 TeV run of the LHC. We consider the gluino pair production process followed by its decay to a top quark and a real or virtual stop squark. The top quark produced from the decay of the gluino can have sufficient transverse momentum to appear as a single fat jet. We apply the jet substructure technique to tag such a hadronically decaying boosted top quark and find that gluino mass up to 1.6 TeV can be discovered whereas exclusion limit extends up to 1.8 TeV at the 14 TeV LHC with 300 $\\rm fb^{-1}$ luminosity. We also briefly discuss the discovery prospect of the boosted stop squark which may be identified as a narrow resonance in the jet mass distribution.
Bhattacherjee, Biplob
OBSERVATION OF TeV GAMMA RAYS FROM THE CYGNUS REGION WITH THE ARGO-YBJ EXPERIMENT
We report the observation of TeV {gamma}-rays from the Cygnus region using the ARGO-YBJ data collected from 2007 November to 2011 August. Several TeV sources are located in this region including the two bright extended MGRO J2019+37 and MGRO J2031+41. According to the Milagro data set, at 20 TeV MGRO J2019+37 is the most significant source apart from the Crab Nebula. No signal from MGRO J2019+37 is detected by the ARGO-YBJ experiment, and the derived flux upper limits at the 90% confidence level for all the events above 600 GeV with medium energy of 3 TeV are lower than the Milagro flux, implying that the source might be variable and hard to be identified as a pulsar wind nebula. The only statistically significant (6.4 standard deviations) {gamma}-ray signal is found from MGRO J2031+41, with a flux consistent with the measurement by Milagro.
Bartoli, B.; Catalanotti, S. [Dipartimento di Fisica dell'Universita di Napoli 'Federico II', Complesso Universitario di Monte Sant'Angelo, via Cinthia, 80126 Napoli (Italy); Bernardini, P.; Bleve, C. [Dipartimento di Fisica dell'Universita del Salento, via per Arnesano, 73100 Lecce (Italy); Bi, X. J.; Cao, Z.; Chen, S. Z.; Chen, Y. [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918, 100049 Beijing (China); Bolognino, I. [Dipartimento di Fisica Nucleare e Teorica dell'Universita di Pavia, via Bassi 6, 27100 Pavia (Italy); Branchini, P.; Budano, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, via della Vasca Navale 84, 00146 Roma (Italy); Calabrese Melcarne, A. K. [Istituto Nazionale di Fisica Nucleare-CNAF, Viale Berti-Pichat 6/2, 40127 Bologna (Italy); Camarri, P. [Dipartimento di Fisica dell'Universita di Roma 'Tor Vergata', via della Ricerca Scientifica 1, 00133 Roma (Italy); Cardarelli, R. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Cattaneo, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, via Bassi 6, 27100 Pavia (Italy); Chen, T. L. [Tibet University, 850000 Lhasa, Xizang (China); Creti, P. [Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); Cui, S. W. [Hebei Normal University, Shijiazhuang 050016, Hebei (China); Dai, B. Z. [Yunnan University, 2 North Cuihu Road, 650091 Kunming, Yunnan (China); D'Ali Staiti, G., E-mail: email@example.com [Dipartimento di Fisica e Tecnologie Relative, Universita degli Studi di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Collaboration: ARGO-YBJ Collaboration; and others
We present models of the extragalactic background light (EBL) based on several scenarios of galaxy formation and evolution. We have treated galaxy formation with the Press-Schecter approximation for both cold dark matter (CDM) and cold+hot dark matter (CHDM) models, representing a moderate ($z_f \\sim 3$) and a late ($z_f \\sim 1$) era of galaxy formation respectively. Galaxy evolution has been treated by considering a variety of stellar types, different initial mass functions and star formation histories, and with an accounting of dust absorption and emission. We find that the dominant factor influencing the EBL is the epoch of galaxy formation. A recently proposed method for observing the EBL utilizing the absorption of $\\sim 0.1$ to 10 TeV gamma-rays from active galactic nuclei (AGN) is shown to be capable of discriminating between different galaxy formation epochs. The one AGN viewed in TeV light, Mrk 421, does show some evidence for a cutoff above 3 TeV; based on the EBL models presented here, we suggest that this is due to extinction in the source. The large absorption predicted at energies $>200$ GeV for sources at $z>0.5$ indicates that observations of TeV gamma-ray bursts (GRB) would constrain or eliminate models in which the GRB sources lie at cosmological distances.
D. MacMinn; J. R. Primack
Baryon and lepton number violation in the electroweak theory at TeV energies
Science Conference Proceedings (OSTI)
In the standard Weinberg-Salam electroweak theory baryon and lepton number (B and L) are NOT exactly conserved. The nonconservation of B and L can be traced to the existence of parity violation in the electroweak theory, together with the chiral current anomaly. This subtle effect gives negligibly small amplitudes for B and L violation at energies and temperatures significantly smaller than M{sub w} sin{sup 2} {theta}{sub w}/{alpha} {approximately} 10 TeV. However, recent theoretical work shows that the rate for B and L nonconservation is unsuppressed at higher energies. The consequences of this for cosmology and the baryon asymmetry of the universe, as well as the prospects for direct verification at the SSC are discussed. 13 refs., 3 figs.
Mottola, E.
Fermi Surface Evolution Across Multiple Charge Density Wave Transitions in ErTe3
Science Conference Proceedings (OSTI)
The Fermi surface (FS) of ErTe{sub 3} is investigated using angle-resolved photoemission spectroscopy (ARPES). Low temperature measurements reveal two incommensurate charge density wave (CDW) gaps created by perpendicular FS nesting vectors. A large {Delta}{sub 1} = 175 meV gap arising from a CDW with c* - q{sub CDW1} {approx} 0.70(0)c* is in good agreement with the expected value. A second, smaller {Delta}{sub 2} = 50 meV gap is due to a second CDW with a* - q{sub CDW2} {approx} 0.68(5)a*. The temperature dependence of the FS, the two gaps and possible interaction between the CDWs are examined.
Moore, R.G.; /SLAC, SSRL /Stanford U., Geballe Lab.; Brouet, V.; /Orsay, LPS; He, R.; /SLAC, SSRL /Stanford U., Geballe Lab.; Lu, D.H.; /SLAC, SSRL; Ru, N.; Chu, J.-H.; Fisher, I.R.; /Stanford U., Geballe Lab.; Shen, Z.-X.; /SLAC, SSRL /Stanford U., Geballe Lab.
Jet structure in 2.76 TeV Pb Pb collisions at ALICE
We present the analysis of the semi-inclusive distribution of reconstructed charged particle jets recoiling from a high pT hadron trigger in central Pb Pb collisions at $\\sqrt{s_{NN}}=2.76$ TeV. We measure, subtract and unfold the large underlying event background in such collisions, utilizing a novel technique that does not impose fragmentation bias on the measured jet population. The Pb Pb measurements are compared to a pp PYTHIA reference distribution generated at the same $\\sqrt{s}$. Modification of jet structure due to quenching is explored by varying the cone radius $R$ (0.2, 0.4) and the lower pT cutoff of charged particle constituents (0.15, 2.0 GeV/$c$).
ALICE Collaboration
Commercial production of thin-film CdTe photovoltaic modules. 1995 annual report
This report presents a general overview of progress made in Golden Photon Inc.`s commercial production of thin-film CdTe photovoltaic modules. It describes the improvement in the number of batch runs processed through substrate deposition, all inter-connection, and encapsulation process steps; a progressive increase in the total number of panels processed each month; an improvement in cumulative process yields; and the continual attention given to modifying operating parameters of each major process step. The report also describes manpower status and staffing issues. The description of the status of subcontract progress includes engineering design; process improvement and development; cost improvement and raw materials; environment, safety, and health; and manufacturing cost and productivity optimization. Milestones and deliverables are also described.
Brog, T.K. [Golden Photon, Inc., CO (United States)
Direct Observation of Room-Temperature Polar Ordering in Colloidal GeTe Nanocrystals
Ferroelectrics and other materials that exhibit spontaneous polar ordering have demonstrated immense promise for applications ranging from non-volatile memories to microelectromechanical systems. However, experimental evidence of polar ordering and effective synthetic strategies for accessing these materials are lacking for low-dimensional nanomaterials. Here, we demonstrate the synthesis of size-controlled nanocrystals of the polar material germanium telluride (GeTe) using colloidal chemistry and provide the first direct evidence of room-temperature polar ordering in nanocrystals less than 5 nm in size using aberration-corrected transmission electron microscopy. Synchrotron x-ray diffraction and Raman studies demonstrate a sizeable polar distortion and a reversible size-dependent polar phase transition in these nanocrystals. The stability of polar ordering in solution-processible nanomaterials suggests an economical avenue to Tbit/in2-density non-volatile memory devices and other applications.
Polking, Mark J.; Zheng, Haimei; Urban, Jeffrey J.; Milliron, Delia J.; Chan, Emory; Caldwell, Marissa A.; Raoux, Simone; Kisielowski, Christian F.; Ager III, Joel W.; Ramesh, Ramamoorthy; Alivisatos, A.P.
LLNL 10(a)(1)(A) Annual Report (TE-053672-2)--2005
This report summarizes research related to Lawrence Livermore National Laboratory's (LLNL) Experimental Test Site, Site 300 (S300), located within Alameda and San Joaquin Counties (Figure 1) and conducted under the 10(a)(1)(A) (Recovery) permit TE-053672-2. This property is held in ownership by the U.S. Department of Energy/National Nuclear Security Administration (NNSA). The 2005 Recovery research at S300 involved fieldwork associated with only two species: Alameda whipsnake (Masticophis lateralis euryxanthus) and the California red-legged frog (Rana aurora draytonii) (RLF). Note: the whipsnake subspecies existing at S300 shows taxonomic variation (generally 50% chaparral whipsnake [Masticophis lateralis] traits) when compared to the Alameda whipsnake (Riemer 1954) and therefore it will be referred to as ''California whipsnake (Masticophis lateralis)'' (CWS) for classification purposes in this report (Swaim 2004).
Woollett, J
Stabilization of High Efficiency CdTe Photovoltaic Modules in Controlled Indoor Light Soaking
Science Conference Proceedings (OSTI)
The performance and stabilization of large-area, high-efficiency 9%, CdTe photovoltaic (PV) modules maintained under controlled light-soaking nominally at 800 Watts/m2 irradiance and 65C module temperature are investigated. Degradation of module performance occurs predominantly in the first few hundred hours of exposure under these conditions; these symptoms included losses in fill factor (FF), open-circuit voltage (Voc), and short-circuit current (Isc), which amount to between 7% and 15% total loss in performance. Higher stabilized performance was achieved with lower copper content in the back contact. Transient effects in module Voc and Isc were observed, suggesting partial annealing thereof when stored under low-light levels. Performance changes are analyzed, aided by monitoring the current-voltage characteristics in situ during exposure.
del Cueto, J. A.; Pruett, J.; Cunningham, D.
Performance of the ATLAS tau trigger with 7 TeV collision data at the LHC
Tau leptons are a fundamental ingredient in the discovery of new physics at the LHC. The reconstruction of hadronic tau decays at the trigger level, although a very challenging task in proton-proton collision environments, allows us to double the sample of tau decays collected, and provides additional discovery power to final states which include tau leptons. In this contribution we show the understanding of the tau trigger system using data collected with the ATLAS detector at the LHC in proton-proton collisions at a center-of-mass energy of 7 TeV. We present the most relevant quantities used in the different stages of the trigger selection, and the trigger efficiencies as a function of ET using tau-like QCD events passing the offline reconstruction and identification selection.
Robinson, M; The ATLAS collaboration
Characterization of detector grade CdZnTe material from Redlen Technologies
Science Conference Proceedings (OSTI)
CdZnTe (or CZT) crystals can be used in a variety of detector-type applications. This large band gap material shows great promise for use as a gamma radiation spectrometer. Historically, the performance of CZT has typically been adversely affected by point defects, structural and compositional heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity) and secondary phases (SP). The synthesis of CZT material has improved greatly with the primary performance limitation being attributed to mainly SP. In this presentation, we describe the extensive characterization of detector grade material that has been treated with post growth annealing to remove the SPs. Some of the analytical methods used in this study included polarized, cross polarized and transmission IR imaging, I-V curves measurements, synchrotron X-ray topography and electron microscopy.
Duff, Martine C.; Burger, Arnold; Groza, Michael; Buliga, Vladimir; Bradley, John P.; Dai, Zurong R.; Teslich, Nick; Black, David R.; Awadalla, Salah A.; Mackenzie, Jason; Chen, Henry (Redlen); (SRNL); (LLNL); (NIST); (Fisk U)
Correlations Between Crystal Defects and Performance of CdZnTe Detectors
Science Conference Proceedings (OSTI)
Poor crystallinity remains a major problem affecting the availability and cost of CdZnTe (CZT) detectors. Point defects are responsible for small gradual charge loss and correlated with the electron clouds' drift times, which allows electronic correction of the output signals to achieve high spectral-resolution even with large-volume CZT detectors. In contrast, extended defects causes significant charge losses, which typically are uncorrelated, and, thus, result in much greater fluctuations of the output signals that cannot be corrected. Although extended defects do not affect all the interaction events, their fraction rapidly increases with the crystal's thickness and volume. In this paper, we summarize our recent results from testing CZT material and detectors that emphasize the particular roles of two types of extended defects, and their contributions to the device's overall performance.
A Bolotnikov; S Babalola; G Camarda; Y Cui; R Gul; S Egarievwe; P Fochuk; M Fuerstnau; J Horace; et al.
Performance Characteristics of Frisch-Ring CdZnTe Detectors
Science Conference Proceedings (OSTI)
The performance characteristics of Frisch-ring CdZnTe (CZT) detectors are described and compared with other types of CZT devices. The Frisch-ring detector is a bar-shaped CZT crystal with a geometrical aspect ratio of /spl sim/1:2. The side surfaces of the detector are coated with an insulating layer followed by a metal layer deposited directly upon the insulator. The simple design operates as a single-carrier device. Despite the simplicity of this approach, its performance depends on many factors that are still not fully understood. We describe results of testing several detectors fabricated from CZT material produced by different vendors and compare the results with numerical simulations of these devices.
Bolotnikov,A.; Camarda, G.; Carini, G.; Fiederle, M.; Li, L.; McGregor, D.; McNeil, W.; Wright, G.; James, R.
Analytical model for event reconstruction in coplanar grid CdZnTe detectors
Coplanar-grid (CPG) particle detectors were designed for materials such as CdZnTe (CZT) in which charge carriers of only one sign have acceptable transport properties. The presence of two independent anode signals allows for a reconstruction of deposited energy based on the difference between the two signals, and a reconstruction of the interaction depth based on the ratio of the amplitudes of the sum and difference of the signals. Energy resolution is greatly improved by modifying the difference signal with an empirically determined weighting factor to correct for the effects of electron trapping. In this paper is introduced a modified interaction depth reconstruction formula which corrects for electron trapping utilizing the same weighting factor used for energy reconstruction. The improvement of this depth reconstruction over simpler formulas is demonstrated. Further corrections due to the contribution of hole transport to the signals are discussed.
Matthew Fritts; J�rgen Durst; Thomas G�pfert; Thomas Wester; Kai Zuber
Analytical model for event reconstruction in coplanar grid CdZnTe detectors
Coplanar-grid (CPG) particle detectors were designed for materials such as CdZnTe (CZT) in which charge carriers of only one sign have acceptable transport properties. The presence of two independent anode signals allows for a reconstruction of deposited energy based on the difference between the two signals, and a reconstruction of the interaction depth based on the ratio of the amplitudes of the sum and difference of the signals. Energy resolution is greatly improved by modifying the difference signal with an empirically determined weighting factor to correct for the effects of electron trapping. In this paper is introduced a modified interaction depth reconstruction formula which corrects for electron trapping utilizing the same weighting factor used for energy reconstruction. The improvement of this depth reconstruction over simpler formulas is demonstrated. Further corrections due to the contribution of hole transport to the signals are discussed.
Fritts, Matthew; G�pfert, Thomas; Wester, Thomas; Zuber, Kai
Evidence for charge Kondo effect in superconducting Tl-doped PbTe
We report results of low-temperature thermodynamic and transport measurements of Pb{sub 1-x}Tl{sub x}Te single crystals for Tl concentrations up to the solubility limit of approximately x = 1.5%. For all doped samples, we observe a low-temperature resistivity upturn that scales in magnitude with the Tl concentration. The temperature and field dependence of this upturn are consistent with a charge Kondo effect involving degenerate Tl valence states differing by two electrons, with a characteristic Kondo temperature T{sub K} {approx} 6 K. The observation of such an effect supports an electronic pairing mechanism for superconductivity in this material and may account for the anomalously high T{sub c} values.
Fisher, I
Sensitivity of an underwater Cerenkov km3 telescope to TeV neutrinos from Galactic Microquasars
In this paper are presented the results of Monte Carlo simulations on the capability of the proposed NEMO-km$^3$ telescope to detect TeV muon neutrinos from Galactic microquasars. For each known microquasar we compute the number of detectable events, together with the atmospheric neutrino and muon background events. We also discuss the detector sensitivity to neutrino fluxes expected from known microquasars, optimizing the event selection also to reject the background; the number of events surviving the event selection are given. The best candidates are the steady microquasars SS433 and GX339-4 for which we estimate a sensitivity of about $5\\cdot10^{-11}$ erg/cm$^2$ s; the predicted fluxes are expected to be well above this sensitivity. For bursting microquasars the most interesting candidates are Cygnus X-3, GRO J1655-40 and XTE J1118+480: their analyses are more complicated because of the stochastic nature of the bursts.
C. Distefano; the NEMO Collaboration
The TeV Energy Spectrum of Mrk 421 Measured in A High Flaring State
The BL Lac object (blazar) Mrk 421 was observed during its outburst in April 2004 with the Whipple 10 m telescope for a total of about 24.5 hours. The measured gamma-ray rate varied substantially over the range from 4 to 10 gamma's/min and eventually exceeded the steady gamma-ray rate of the Crab Nebula (standard candle) by a factor of 3. The overall significance of the gamma-ray signal exceeded 70 sigma and the total number of excess events was more than 10,000. The signal light curve does not show any particular variability pattern. This unique Mrk 421 outburst enabled the measurement of a high quality spectrum of very high-energy gamma rays in a high state of emission. This spectrum is a power-law and it extends beyond 10 TeV.
A. Konopelko; W. Cui; C. Duke; J. P. Finley
Exploring the powering source of the TeV X-ray binary LS 5039
LS 5039 is one of the four TeV emitting X-ray binaries detected up to now. The powering source of its multi-wavelength emission can be accretion in a microquasar scenario or wind interaction in a young non-accreting pulsar scenario. These two scenarios predict different morphologic and peak position changes along the orbital cycle of 3.9 days, which can be tested at milliarcsecond scales using VLBI techniques. Here we present a campaign of 5 GHz VLBA observations conducted in June 2000 (2 runs five days apart). The results show a core component with a constant flux density, and a fast change in the morphology and the position angle of the elongated extended emission, but maintaining a stable flux density. These results are difficult to fit comfortably within a microquasar scenario, whereas they appear to be compatible with the predicted behavior for a non-accreting pulsar.
J. Moldon; M. Ribo; Josep M. Paredes; J. Marti; M. Massi
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
solvents solvents B-6 Pre-Combustion solvents u.s. DePartment of energy aDvanCeD Carbon DioxiDe CaPture r&D Program: teChnology uPDate, may 2013 Co 2 CaPture from igCC gas streams using aC-abC ProCess primary project goals SRI International is developing, for integrated gasification combined cycle (IGCC)-based power plants, a carbon dioxide (CO 2 ) capture technology based on the use of a high-ca- pacity and low-cost aqueous ammoniated solution containing ammonium carbonate (AC), which reacts with CO 2 to form ammonium bicarbonate (ABC).
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
solvents solvents B-198 Post-Combustion solvents u.s. DePartment of energy aDvanCeD Carbon DioxiDe CaPture r&D Program: teChnology uPDate, may 2013 DeveloPment anD Demonstration of Waste heat integration With solvent ProCess for more effiCient Co 2 removal from Coal-fireD flue gas primary project goals Southern Company Services is developing viable heat integration methods for the capture of carbon dioxide (CO 2 ) produced from pulverized coal (PC) combustion. The project will quantify energy-efficiency improvements to the CO 2 capture process by utilizing a waste heat recovery technology, High-Efficiency System (HES). technical goals * Reduction of the amount of extraction steam required for sensible heat load in the
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
sorbents sorbents B-302 Post-Combustion sorbents u.s. DePartment of energy aDvanCeD Carbon DioxiDe CaPture r&D Program: teChnology uPDate, may 2013 benCh-sCale DeveloPment anD testing of raPiD Pressure swing absorPtion for Carbon DioxiDe CaPture primary project goals WR Grace and the University of South Carolina are developing a rapid pressure swing adsorption (PSA) process to evaluate concept cost and performance benefits by testing a bench-scale system using a low-cost, structured adsorbent with low-pressure drop, high mass-transfer rates, high capacity, and high availability that will enable large feed through- puts. technical goals * Develop an attrition-resistant and low-pressure drop structured adsorbent based on a
Appendix B: CArBon dioxide CApture teChnology SheetS
NLE Websites -- All DOE Office Websites (Extended Search)
membranes membranes B-370 Post-Combustion membranes u.s. DePartment of energy aDvanCeD Carbon DioxiDe CaPture r&D Program: teChnology uPDate, may 2013 eleCtroChemiCal membrane for Carbon DioxiDe CaPture & Power generation primary project goals FuelCell Energy, Inc. (FCE) is developing an electrochemical membrane (ECM)-based Combined Electric Power and Carbon Dioxide Separation (CEPACS) system for carbon dioxide (CO 2 ) capture that also provides additional electrical power generation. The project includes bench-scale testing of an 11.7 m 2 -area ECM (molten carbonate fuel cell) system for CO 2 capture, purification, and compression. technical goals * Perform contaminant effect testing to establish maximum permissible concentrations of
Hiding a Heavy Higgs Boson at the 7 TeV LHC
Science Conference Proceedings (OSTI)
A heavy Standard Model Higgs boson is not only disfavored by electroweak precision observables but is also excluded by direct searches at the 7 TeV LHC for a wide range of masses. Here, we examine scenarios where a heavy Higgs boson can be made consistent with both the indirect constraints and the direct null searches by adding only one new particle beyond the Standard Model. This new particle should be a weak multiplet in order to have additional contributions to the oblique parameters. If it is a color singlet, we find that a heavy Higgs with an intermediate mass of 200-300 GeV can decay into the new states, suppressing the branching ratios for the standard model modes, and thus hiding a heavy Higgs at the LHC. If the new particle is also charged under QCD, the Higgs production cross section from gluon fusion can be reduced significantly due to the new colored particle one-loop contribution. Current collider constraints on the new particles allow for viable parameter space to exist in order to hide a heavy Higgs boson. We categorize the general signatures of these new particles, identify favored regions of their parameter space and point out that discovering or excluding them at the LHC can provide important indirect information for a heavy Higgs. Finally, for a very heavy Higgs boson, beyond the search limit at the 7 TeV LHC, we discuss three additional scenarios where models would be consistent with electroweak precision tests: including an additional vector-like fermion mixing with the top quark, adding another U(1) gauge boson and modifying triple-gauge boson couplings.
Bai, Yang; Fan, JiJi; Hewett, JoAnne L.
Thin film gold/polycrystalline cadmium telluride Schottky solar cells made by electrodepositing the semiconductor on an ITO-coated glass substrate serving also as an ohmic contact demonstrated an internal efficiency of 4% over 2 mm/sup 2/ areas. During the year being reported upon, Monosolar devoted mator attention to refining the electroplating process and determining the parameters governing CdTe film stoichiometry, grain size, substrate adhesion, and quality. UCLA acting as a Monosolar sub-contractor characterized both the CdTe films themselves and solar cells made from them. Techniques were developed for making measurements on films often less than 1 micron in thickness. The highest values achieved for efficiency parameters, not necessarily all in the same cell, were V/sub oc/ = 0.5 V, J/sub sc/ = 11 mA/cm/sup 2/, and fill factor = 0.55 before corrections in the absence of anti-reflection coatings. Typical resistivities for n-CdTe films were 10/sup 5/ ..cap omega..-cm. Lifetimes of about 10/sup -10/ sec were measured. Absorption coefficient of these films is in the order of 10/sup 4/ for lambda < 0.7 ..mu..m. Measured energy gap for these CdTe films is 1.55 eV, sightly higher than the 1.45 eV value for single crystal CdTe. The activation energy of the dominating trap level is 0.55 eV. Trap density is in the order of 10/sup 16//cm/sup 3/. Schottky diodes were of excellent quality and pinhole-free. The measured barrier height varied between 0.75 and 0.85 eV. Rectification ratios of 10/sup 4/ were obtained reproducibly. Films measure about 1 inch square. Indications are that larger and more efficient low cost solar devices can readily be obtained soon using the techniques developed in this program.
Rod, R.L.; Bunshah, R.; Stafsudd, O.; Basol, B.M.; Nath, P.
BLAZARS AS ULTRA-HIGH-ENERGY COSMIC-RAY SOURCES: IMPLICATIONS FOR TeV GAMMA-RAY OBSERVATIONS
Science Conference Proceedings (OSTI)
The spectra of BL Lac objects and Fanaroff-Riley I radio galaxies are commonly explained by the one-zone leptonic synchrotron self-Compton (SSC) model. Spectral modeling of correlated multiwavelength data gives the comoving magnetic field strength, the bulk outflow Lorentz factor, and the emission region size. Assuming the validity of the SSC model, the Hillas condition shows that only in rare cases such sources accelerate protons to much above 10{sup 19} eV, so {approx}> 10{sup 20} eV ultra-high-energy cosmic rays (UHECRs) are likely to be heavy ions if powered by this type of radio-loud active galactic nuclei (AGNs). Survival of nuclei is shown to be possible in TeV BL Lacs and misaligned counterparts with weak photohadronic emissions. Another signature of hadronic production is intergalactic UHECR-induced cascade emission, which is an alternative explanation of the TeV spectra of some extreme non-variable blazars such as 1ES 0229+200 or 1ES 1101-232. We study this kind of cascade signal, taking into account effects of the structured extragalactic magnetic fields in which the sources should be embedded. We demonstrate the importance of cosmic-ray deflections on the {gamma}-ray flux, and show that required absolute cosmic-ray luminosities are larger than the average UHECR luminosity inferred from UHECR observations and can even be comparable to the Eddington luminosity of supermassive black holes. Future TeV {gamma}-ray observations using the Cerenkov Telescope Array and the High Altitude Water Cerenkov detector array can test for UHECR acceleration by observing >25 TeV photons from relatively low redshift sources such as 1ES 0229+200, and {approx}>TeV photons from more distant radio-loud AGNs.
Murase, Kohta [Department of Physics, Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Dermer, Charles D. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Takami, Hajime [Max Planck Institute for Physics, Foehringer Ring 6, 80805 Munich (Germany); Migliori, Giulia [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
This is an annual technical report on the Phase 2 of a three-year phased research program. The principal objective of the research project is to develop novel and low-cost processes for the fabrication of stable and efficient CuIn{sub 1{minus}x}Ga{sub x}Se{sub 2} and CdTe polycrystalline-thin-film solar cells using reliable techniques amenable to scale-up for economic, large-scale manufacture. The aims are to develop a process for the non-toxic selenization so as to avoid the use of extremely toxic H{sub 2}Se in the fabrication of CuIn{sub 1{minus}x}Ga{sub x}Se{sub 2} thin-film solar cells; to optimize selenization parameters; to develop a process for the fabrication of CdTe solar cells using Cd and Te layers sputtered from elemental targets; to develop an integrated process for promoting the interdiffusion between Cd/Te layers, CdTe phase formation, grain growth, type conversion, and junction formation; to improve adhesion; to minimize residual stresses; to improve the metallic back-contact; to improve the uniformity, stoichiometry, and morphology of CuIn{sub 1{minus}x}Ga{sub x}Se{sub 2} and CdTe thin films; and to improve the efficiency of CuIn{sub 1{minus}x}Ga{sub x}Se{sub 2} and CdTe solar cells.
Dhere, N.G. [Florida Solar Energy Center, Cape Canaveral, FL (United States)
The principal objective of the research project is to develop processes for the fabrication of cadmium-telluride, CdTe, and copper-indium-gallium-diselenide, Cu(In{sub 1{minus}x}Ga{sub x})Se{sub 2}, polycrystalline-thin-film solar cells using techniques that can be scaled-up for economic manufacture on a large scale. The aims are to fabricate CdTe solar cells using Cd and Te layers sputtered from elemental targets; to promote the interdiffusion between Cd/Te layers, CdTe phase formation, and grain growth; to utilize non-toxic selenization so as to avoid the use of extremely toxic H{sub 2}Se in the fabrication of Cu(In{sub l{minus}x}Ga{sub x})Se{sub 2} thin-film solar cells; to optimize selenization parameters; to improve adhesion; to minimize residual stresses; to improve the uniformity, stoichiometry, and morphology of CdTe and Cu(In{sub 1{minus}x}Ga{sub x})Se{sub 2} thin films, and the efficiency of CdTe and Cu(In{sub 1{minus}x}Ga{sub x})Se{sub 2} solar cells.
Dhere, N.G. [Florida Solar Energy Center, Cape Canaveral, FL (United States)
We describe the design of a time resolved photoluminescence (TRPL) spectrometer for rapid semiconductor absorber characterization. Simplicity and flexibility is achieved by using single optical fiber to deliver laser pulses and to collect photoluminescence. We apply TRPL for characterization of CdS/CdTe absorbers after deposition, CdCl2 treatment, Cu doping, and back contact formation. Data suggest this method could be applied in various stages of PV device processing. Finally, we show how to analyze TRPL data for CdS/CdTe absorbers by considering laser light absorption depth and intermixing at CdS/CdTe interface.
Kuciauskas, D.; Duenow, J. N.; Kanevce, A.; Li, J. V.; Young, M. R.; Dippo, P.; Levi, D. H.
The production of Y(1S), Y(2S), and Y(3S) is investigated in pPb and pp collisions at centre-of-mass energies per nucleon pair of 5.02 TeV and 2.76 TeV, respectively. The datasets correspond to integrated luminosities of about 31 inverse nanobarns (pPb) and 5.4 inverse picobarns (pp), collected in 2013 by the CMS experiment at the LHC. Upsilons that decay into muons are reconstructed within the rapidity interval abs(y[CM]), are found to rise with both measures of the event activity in pp and pPb. In both collision systems, the ratios of the excited to the ground state cross s...
Chatrchyan, Serguei; CMS Collaboration; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Er�, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hartl, Christian; H�rmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Kn�nz, Valentin; Krammer, Manfred; Kr�tschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Herbert; Sch�fbeck, Robert; Strauss, Josef; Taurok, Anton; Treberer-Treberspurg, Wolfgang; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Knutsson, Albert; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Heracleous, Natalie; Kalogeropoulos, Alexis; Keaveney, James; Kim, Tae Jeong; Lowette, Steven; Maes, Michael; Olbrechts, Annik; Strom, Derek; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Caillol, C�cile; Clerbaux, Barbara; De Lentdecker, Gilles; Favart, Laurent; Gay, Arnaud; Hreus, Tomas; L�onard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Perni�, Luca; Reis, Thomas; Seva, Tomislav; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Benucci, Leonardo; Cimmino, Anna; Costantini, Silvia; Dildick, Sven; Garcia, Guillaume; Klein, Benjamin; Lellouch, J�r�mie; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Sigamani, Michael; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Beluffi, Camille; Bruno, Giacomo; Castello, Roberto; Caudron, Adrien; Ceard, Ludivine; Da Silveira, Gustavo Gil; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Jez, Pavel; Komm, Matthias; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Popov, Andrey; Quertenmont, Loic; Selvaggi, Michele; Vidal Marono, Miguel; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Ald� J�nior, Walter Luiz; Carvalho, Wagner; Chinellato, Jose; Cust�dio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Malek, Magdalena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santaolalla, Javier; Santoro, Alberto; Sznajder, Andre; Tonelli Manganote, Edmilson Jos�; Vilela Pereira, Antonio; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Marinov, Andrey; Piperov, Stefan; Rodozov, Mircho; Sultanov, Georgi; Vutova, Mariana; Dimitrov, Anton; Glushkov, Ivan; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Chen, Mingshui; Du, Ran; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Plestina, Roko; Tao, Junquan; Wang, Xianyou; Wang, Zheng; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Dayong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Carrillo Montoya, Camilo Andres; Chaparro Sierra, Luisa Fernanda; Florez, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Morovic, Srecko; Tikvica, Lucija; Attikis, Alexandros; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Abdelalim, Ahmed Ali; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; M�ntel, Mait; Murumaa, Marion; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; H�rk�nen, Jaakko; Karim�ki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lamp�n, Tapio; Lassila-Perini, Kati
The potential of photovoltaics to become a major global business enterprise still lingers outside the limits of industrial capabilities. For the Cadmium Sulfide/Cadmium Telluride (CdS/CdTe) system this potential has continued to focus on improvements in efficiency, stability, and cost reduction. This triad is the primary objective of the present subcontract with NREL entitled {open_quotes}The Improvement of Near-term CdTe Processing and Product Capabilities & Establishment of Next Generation CdTe Technology{close_quotes}. This subcontract represents an intermediate stage of NREL`s plan to assist the growth of the photovoltaic industry in overcoming the scientific and technical barriers to commercialization. This report outlines the progress that has been made during the period of August 1995 through August 1996. The objectives of this subcontract are to improve processing methods, quantify and understand efficiency improvement mechanisms, meet life-testing goals, and address cadmium safety concerns. Task and subtask goals are defined to meet these objectives in specific areas. The approach to fulfilling the subcontract goals is through a balanced plan of process improvement and mechanism identification. These are carried out and continued through monitoring under various long term and accelerated stress conditions. GPI maintains an on-going awareness of all safety related issues, can in particular, those involving cadmium.
Kester, J.; Albright, S. [Golden Photon, Inc., CO (United States)
Science Conference Proceedings (OSTI)
The objective of this work was to investigate the effect of deviation from stoichiometry on the electrophysical properties (electrical and thermal conductivity, thermoelectric power, and carrier concentration) of the ternary layered semiconducting compounds Ge{sub 3{plus_minus}{delta}1}Bi{sub 2+{delta}2}Te{sub 6+{delta}3} and Ge{sub 1{plus_minus}{delta}3}, which are promising for use in thermoelectric converters.The electrophysical properties were measured at 300 K. The Ge{sub 1-{delta}1}Bi{sub 2+{delta}3} alloys were studied by powder X-ray diffraction analysis on a DRON UM-1 diffractometer (CoK{sub {alpha}} radiation). It was found that Ge{sub 3{plus_minus}{delta}1} Bi{sub 2+{delta}2}Te{sub 6{plus_minus}{delta}3} is a nonstoichiometric phase with p-type conductivity throughout the {delta}{sub 1}, {delta}{sub 2}, and {delta}{sub 3} ranges examined. Our results suggest that cation vacancies are likely to be the dominant nonstoichiometric defects responsible for the high concentration of holes. The conductivity of Ge{sub 1{plus_minus}{delta}1}Bi{sub 2}Te{sub 4} changes from the p-type in the Ge-deficient alloys to the n-type in the Gerich alloys.
Shelimova, L.E.; Karpinskii, O.G.; Avilov, E.S.; Kretova, M.A.; Lubman, C.U. [Baikov Institute of Metallurgy, Moscow (Russian Federation)
This paper describes the large concentration of 60..deg.. <111> twin boundaries that was observed in every CdTe film analyzed in this work, even after recrystallization and grain growth, confirming the low energy of these interfaces.
Mountinho, H. R.; Dhere, R. G.; Romero, M. J.; Jiang, C. S.; To, B.; Al-Jassim, M. M.
In this work we investigated different methods to prepare cross sections of CdTe/CdS solar cells for EBSD and SKPM analyses. We observed that procedures used to prepare surfaces for EBSD are not suitable to prepare cross sections, and we were able to develop a process using polishing and ion-beam milling. This process resulted in very good results and allowed us to reveal important aspects of the cross section of the CdTe film. For SKPM, polishing and a light ion-beam milling resulted in cross sections that provided good data. We were able to observe the depletion region on the CdTe film and the p-n junction as well as the interdiffusion layer between CdTe and CdS. However, preparing good-quality cross sections for SKPM is not a reproducible process, and artifacts are often observed.
Moutinho, H. R.; Dhere, R. G.; Jiang, C. S.; Al-Jassim, M. M.
X-ray diffraction study of (TlInSe{sub 2}){sub 1-x}(TlGaTe{sub 2}){sub x} crystal system
Science Conference Proceedings (OSTI)
The crystallographic and dynamic characteristics of TlInSe{sub 2} and TlGaTe{sub 2} crystals have been studied by X-ray diffraction in the temperature range of 85-320 K. The temperature dependences of the unit-cell parameters a of TlInSe{sub 2} and TlGaTe{sub 2} crystals, as well as their coefficients of thermal expansion along the [100] direction, are determined. The concentration dependences of the unit-cell parameters a and c for (TlInSe{sub 2}){sub 1-x}(TlGaTe{sub 2}){sub x} crystals are measured. Anomalies are found in the temperature dependences of the unit-cell parameters a and, correspondingly, the coefficient of thermal expansion, indicating the existence of phase transitions in TlInSe{sub 2} and TlGaTe{sub 2} crystals.
Sheleg, A. U., E-mail: firstname.lastname@example.com; Zub, E. M.; Yachkovskii, A. Ya. [National Academy of Sciences of Belarus, State Scientific and Production Association, Scientific and Practical Materials Research Center (Belarus); Mustafaeva, S. N.; Kerimova, E. M. [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan)
A search for the Higgs boson has been performed in the H?WW[superscript (*)]??[superscript +]??[superscript -]?? channel (?=e/?) with an integrated luminosity of 2.05??fb[superscript -1] of pp collisions at ?s=7??TeV ...
Taylor, Frank E.
Growth and structure of photosensitive Pb{sub 1-x}Mn{sub x}Te(Ga) epitaxial films
Science Conference Proceedings (OSTI)
The growth and structure of (1-1.5)-{mu}m-thick Pb{sub 1-x}Mn{sub x}Te(Ga)(x = 0.06) films with 0.4-0.9 at % of gallium, grown on BaF{sub 2}(111) and Pb{sub 1-x}Sn{sub x}Te (x = 0.2) (100) substrates by molecular beam epitaxy, have been investigated. It is established that the films are crystallized into an fcc structure, and their growth planes are (111) and (100), according to the substrate orientation. The optimal conditions for obtaining high-resistivity photosensitive p-and n-type films with a perfect crystal structure (W{sub 1/2} = 80''-100'') have been determined.
Nuriev, I. R.; Sadygov, R. M.; Nazarov, A. M., E-mail: email@example.com [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan)
Molecular beam epitaxy growth of PbSe on Si (211) using a ZnTe buffer layer
Science Conference Proceedings (OSTI)
The authors report the results of successful growth of single crystalline PbSe on Si (211) substrates with ZnTe as a buffer layer by molecular beam epitaxy. Single crystalline PbSe with (511) orientation was achieved on ZnTe/Si (211), as evidenced by RHEED patterns indicative of 2 dimensional (2D) growth, x ray diffraction rocking curves with a full width at half maximum as low as 153 arc sec and mobility as large as 1.1x10{sup 4}cm{sup 2}V{sup -1}s{sup -1} at 77 K. Cross hatch patterns were found on the PbSe(511) surface in Nomarski filtered microscope images suggesting the presence of a surface thermal strain relaxation mechanism, which was confirmed by Fourier transformed high resolution transmission electron microscope images.
Wang, X. J.; Chang, Y.; Hou, Y. B.; Becker, C. R.; Kodama, R.; Aqariden, F.; Sivananthan, S. [Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 (United States); Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 and Physics Department and Quantum Functional Semiconductor Research Center, Dongguk University 3-26, Seoul 100-715 (Korea, Republic of); Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 (United States); EPIR Technologies, Bolingbrook, Illinois 60440 (United States); Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 and EPIR Technologies, Bolingbrook, Illinois 60440 (United States)
Investigation of Charge Transport Properties of CdZnTe Detectors with Synchrotron X-ray Radiation
Science Conference Proceedings (OSTI)
Various internal defects, such as Te inclusions, twin boundaries, dislocation, etc., are prevalent in as-grown CdZnTe (CZT) crystals, which affect the charge transport properties of CZT crystals and, therefore, worsen the performance of CZT detectors. In order to develop high quality CZT detectors, it is imperative to clarify the effects of internal defects on the charge transport properties of CZT. Simple flood illumination with nuclear radiation source cannot reveal the nature of highly localized defects in CZT. Therefore, at Brookhaven's National Synchrotron Light Source (NSLS), we have developed a unique testing system for micro-scale defect investigation of CZT, which employs an X-ray beam collimated with the spatial resolution as small as 3 x 3 {micro}m{sup 2}, a microscopic size comparable to the scale of common defects in CZT. This powerful tool enables us to investigate the effect of internal defects on charge transport properties of CZT in detail.
Yang,G.; Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Hossain, A.; James, R.B.
High-efficiency large-area CdTe panels. Final subcontract report, June 1987--July 1990
The objective of this three year effort has been to develop an improved materials technology and fabrication process for limited volume production of 1 ft{sup 2} and 4 ft{sup 2} CdS/CdTe photovoltaic modules. The module stability objective by the end of this three year subcontract was to develop techniques to provide ten year life exploration with no greater than 10% degradation. In order to achieve these efficiency and stability objectives, the research program has been separated into tasks including: (1) analysis and characterization of CdS/CdTe Devices; (2) performance optimization on small cells; (3) encapsulation and stability testing; and (4) module efficiency optimization. 27 refs., 18 figs., 3 tabs.
Albright, S.P.; Chamberlin, R.R.; Jordan, J.F. [Photon Energy, Inc., El Paso, TX (USA)
The Effect of High-Resistance SnO2 on CdS/CdTe Device Performance
In this paper, we have studied the effect of high-resistance SnO2 buffer layers, deposited by low-pressure chemical-vapor deposition, on CdS/CdTe device performance. Our results indicate that when CdS/CdTe devices have a very thin layer of CdS or no CdS at all, the i-SnO2 buffer layer helps to increase device efficiency. When the CdS layer is thicker than 600{angstrom}, the device performance is dominated by CdS thickness, not the i-SnO2 layer. If a very thin CdS layer is to be used to enhance device performance, we conclude that a better SnO2 buffer layer is needed.
Li, W.; Ribelin, R.; Mahathongdy, Y.; Albin, D.; Dhere, R.; Rose, D.; Asher, S.; Moutinho, H.; Sheldon, P.
Science Conference Proceedings (OSTI)
High-spin states have been populated in {sub 52}{sup 110}Te via {sup 58}Ni({sup 58}Ni,{alpha}2p{gamma}) reactions at 240 and 250 MeV. The Gammasphere {gamma}-ray spectrometer was used in conjunction with the Microball charged-particle detector. The high-spin (I>30) collective level scheme of {sup 110}Te, up to {approx}45({Dirac_h}/2{pi}), is discussed in this paper. Four new decoupled ({delta}I=2) high-spin structures have been observed for the first time, together with two strongly coupled ({delta}I=1) bands. These bands all show the characteristics of smooth band termination, and are discussed within the framework of the cranked Nilsson-Strutinsky approach.
Paul, E. S.; Evans, A. O.; Boston, A. J.; Nolan, P. J.; Semple, A. T. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Chiara, C. J.; Fossan, D. B.; Lane, G. J.; Sears, J. M.; Starosta, K. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Devlin, M.; LaFosse, D. R.; Sarantites, D. G. [Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States); Freeman, S. J.; Leddy, M. J. [Schuster Laboratory, The University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Lee, I. Y.; Macchiavelli, A. O. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Smith, J. F. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Schuster Laboratory, The University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Afanasjev, A. V. [Department of Physics and Astronomy, Mississippi State University, Mississippi 39762 (United States); Department of Mathematical Physics, Lund Institute of Technology, P. O. Box 118, S-22100 Lund (Sweden); Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31 (Latvia); Ragnarsson, I. [Department of Mathematical Physics, Lund Institute of Technology, P. O. Box 118, S-22100 Lund (Sweden)
Development of a computer model for polycrystalline thin-film CuInSe sub 2 and CdTe solar cells
This report describes work to develop a highly accurate numerical model for CuInSe{sub 2} and CdTe solar cells. ADEPT (A Device Emulation Program and Toolbox), a one-dimensional semiconductor device simulation code developed at Purdue University, was used as the basis of this model. An additional objective was to use ADEPT to analyze the performance of existing and proposed CuInSe{sub 2} and CdTe solar cell structures. The work is being performed in two phases. The first phase involved collecting device performance parameters, cell structure information, and material parameters. This information was used to construct the basic models to simulate CuInSe{sub 2} and CdTe solar cells. This report is a tabulation of information gathered during the first phase of this project on the performance of existing CuInSe{sub 2} and CdTe solar cells, the material properties of CuInSr{sub 2}, CdTe, and CdS, and the optical absorption properties of CuInSe{sub 2}, CdTe, and CdS. The second phase will entail further development and the release of a version of ADEPT tailored to CuInSe{sub 2} and CdTe solar cells that can be run on a personal computer. In addition, ADEPT will be used to analyze the performance of existing and proposed CuInSe{sub 2} and CdTe solar cell structures. 110 refs.
Gray, J.L.; Schwartz, R.J.; Lee, Y.J. (Purdue Univ., Lafayette, IN (United States))
Appendix B: CArBon dioxide CApture teChnology SheetS R&D CollaboRation...
NLE Websites -- All DOE Office Websites (Extended Search)
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On the Origin of TeV Gamma-ray Emission from HESS J1834-087
We present an X-ray study of the field containing the extended TeV source HESS J1834-087 using data obtained with the XMM-Newton telescope. Previously, the coincidence of this source with both the shell-type supernova remnant (SNR) W41 and a giant molecular cloud (GMC) was interpreted as favoring pi^0-decay gamma-rays from interaction of the old SNR with the GMC. Alternatively, the TeV emission has been attributed to inverse Compton scattering from leptons deposited by PSR J1833-0827, a pulsar assumed to have been born in W41 but now located 24' from the center of the SNR (and the TeV source). Instead, we argue for a third possibility, that the TeV emission is powered by a previously unknown pulsar wind nebula located near the center of W41. The candidate pulsar is XMMU J183435.3-084443, a hard X-ray point source that lacks an optical counterpart to R>21 and is coincident with diffuse X-ray emission. The X-rays from both the point source and diffuse feature are evidently non-thermal and highly absorbed. A best fit power-law model yields photon index Gamma ~ 0.2 and Gamma ~ 1.9, for the point source and diffuse emission, respectively, and 2-10 keV flux ~ 5 X 10^(-13) ergs/cm^(2)/s for each. At the measured 4 kpc distance of W41, the observed X-ray luminosity implies an energetic pulsar with Edot ~ 10^(36)d_4^2 ergs/s, which is also sufficient to generate the observed gamma-ray luminosity of 2.7 X 10^(34)d_4^2 ergs/s via inverse Compton scattering.
R. Mukherjee; E. V. Gotthelf; J. P. Halpern
A search for GeV-TeV emission from Gamma-ray Bursts using the Milagro detector
A search for GeV-TeV emission from Gamma-ray Bursts using the Milagro detector p. M. Saz Parkinson of operation. Keywords: gamma-ray sources; gamma-ray bursts; astronomical observations gamma-ray; gamma-ray telescope; Milagro PACS: 95.55.Ka; 95.85.Pw; 98.70.Rz INTRODUCTION Gamma-ray bursts (GRBs) were detected up
California at Santa Cruz, University of
Diffraction gratings in ray tracing
simply switching out the shader for the CD material surfaceThis code is added to the shader function for any rendering
Watson, Andre James
The effects of the band bending caused by interface states in CdTe and CIS solar cells
In this paper, the effects of interface states in the Z-nO/CdS/CuinSe{sub 2}, and CdS/CdTe solar cells are presented. The effects are investigated through numerical modeling using ADEPT (A Device Emulation Program and Too