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Office of Scientific and Technical Information
Si deposition rates in a two-dimensional CVD (chemical vapor deposition) reactor and comparisons with model calculations
SciTech Connect
Deposition rates are presented for silicon from silane in a helium carrier gas using a tubular CVD reactor with a two-dimensional flow geometry. Measured surface-temperature profiles, inlet gas velocities, total pressures, and silane/helium concentrations are reported, providing exact boundary conditions that can be used in a two-dimensional numerical CVD model. Comparisons are made between this data and two variations of a model by Coltrin, Kee, and Miller in which different empirical expressions for the silane and disilane reactive sticking coefficient are used.
Breiland, W.G.; Coltrin, M.E.
Method and apparatus for removing and preventing window deposition during photochemical vapor deposition (photo-CVD) processes
DOE Patents (OSTI)
Unwanted build-up of the film deposited on the transparent light-transmitting window of a photochemical vacuum deposition (photo-CVD) chamber is eliminated by flowing an etchant into the part of the photolysis region in the chamber immediately adjacent the window and remote from the substrate and from the process gas inlet. The respective flows of the etchant and the process gas are balanced to confine the etchant reaction to the part of the photolysis region proximate to the window and remote from the substrate. The etchant is preferably one that etches film deposit on the window, does not etch or affect the window itself, and does not produce reaction by-products that are deleterious to either the desired film deposited on the substrate or to the photolysis reaction adjacent the substrate.
Tsuo, Simon (Lakewood, CO); Langford, Alison A. (Boulder, CO)
Unwanted build-up of the film deposited on the transparent light-transmitting window of a photochemical vacuum deposition (photo-CVD) chamber is eliminated by flowing an etchant into the part of the photolysis region in the chamber immediately adjacent the window and remote from the substrate and from the process gas inlet. The respective flows of the etchant and the process gas are balanced to confine the etchant reaction to the part of the photolysis region proximate to the window and remote from the substrate. The etchant is preferably one that etches film deposit on the window, does not etch or affect the window itself, and does not produce reaction by-products that are deleterious to either the desired film deposited on the substrate or to the photolysis reaction adjacent the substrate. 3 figs.
Tsuo, S.; Langford, A.A.
Chemical vapor deposition sciences
Chemical vapor deposition (CVD) is a widely used method for depositing thin films of a variety of materials. Applications of CVD range from the fabrication of microelectronic devices to the deposition of protective coatings. New CVD processes are increasingly complex, with stringent requirements that make it more difficult to commercialize them in a timely fashion. However, a clear understanding of the fundamental science underlying a CVD process, as expressed through computer models, can substantially shorten the time required for reactor and process development. Research scientists at Sandia use a wide range of experimental and theoretical techniques for investigating the science of CVD. Experimental tools include optical probes for gas-phase and surface processes, a range of surface analytic techniques, molecular beam methods for gas/surface kinetics, flow visualization techniques and state-of-the-art crystal growth reactors. The theoretical strategy uses a structured approach to describe the coupled gas-phase and gas-surface chemistry, fluid dynamics, heat and mass transfer of a CVD process. The software used to describe chemical reaction mechanisms is easily adapted to codes that model a variety of reactor geometries. Carefully chosen experiments provide critical information on the chemical species, gas temperatures and flows that are necessary for model development and validation. This brochure provides basic information on Sandia`s capabilities in the physical and chemical sciences of CVD and related materials processing technologies. It contains a brief description of the major scientific and technical capabilities of the CVD staff and facilities, and a brief discussion of the approach that the staff uses to advance the scientific understanding of CVD processes.
Chemical vapor deposition of mullite coatings
This invention is directed to the creation of crystalline mullite coatings having uniform microstructure by chemical vapor deposition (CVD). The process comprises the steps of establishing a flow of reactants which will yield mullite in a CVD reactor, and depositing a crystalline coating from the reactant flow. The process will yield crystalline coatings which are dense and of uniform thickness.
Sarin, Vinod (Lexington, MA); Mulpuri, Rao (Boston, MA)
Chemical vapor deposition of antimicrobial polymer coatings
E-Print Network (OSTI)
There is large and growing interest in making a wide variety of materials and surfaces antimicrobial. Initiated chemical vapor deposition (iCVD), a solventless low-temperature process, is used to form thin films of polymers ...
Martin, Tyler Philip, 1977-
Oxidative chemical vapor deposition of conductive polymers for use in novel photovoltaic device architectures
The conductive polymer poly(3,4-ethylenedioxythiophene), (PEDOT), deposited via oxidative chemical vapor deposition (oCVD) has been investigated for use in organic electronic devices. The oCVD process as well as the ...
Howden, Rachel M. (Rachel Mary)
Chemical vapor deposition of organosilicon and sacrificial polymer thin films
Chemical vapor deposition (CVD) produced films for a wide array of applications from a variety of organosilicon and organic precursors. The structure and properties of thin films were controlled by varying processing ...
Casserly, Thomas Bryan
Initiated chemical vapor deposition of functional polyacrylic thin films
Initiated chemical vapor deposition (iCVD) was explored as a novel method for synthesis of functional polyacrylic thin films. The process introduces a peroxide initiator, which can be decomposed at low temperatures (<200?C) ...
Mao, Yu, 1975-
Initiated chemical vapor deposition of polymeric thin films : mechanism and applications
Initiated chemical vapor deposition (iCVD) is a novel technique for depositing polymeric thin films. It is able to deposit thin films of application-specific polymers in one step without using any solvents. Its uniqueness ...
Chan, Kelvin, Ph. D. Massachusetts Institute of Technology
Chemical vapor deposition of amorphous semiconductor films. Final subcontract report
DOE Green Energy (OSTI)
Chemical vapor deposition (CVD) from higher order silanes has been studied for fabricating amorphous hydrogenated silicon thin-film solar cells. Intrinsic and doped a-Si:H films were deposited in a reduced-pressure, tubular-flow reactor, using disilane feed-gas. Conditions for depositing intrinsic films at growth rates up to 10 A/s were identified. Electrical and optical properties, including dark conductivity, photoconductivity, activation energy, optical absorption, band-gap and sub-band-gap absorption properties of CVD intrinsic material were characterized. Parameter space for depositing intrinsic and doped films, suitable for device analysis, was identified.
Rocheleau, R.E.
Dynamics of nucleation in chemical vapor deposition
Science Conference Proceedings (OSTI)
We study the evolution of layer morphology during the early stages of metal chemical vapor deposition (CVD) onto Si(100) via pyrolysis of Fe(CO){sub 5} below 250{degrees}C. Scanning tunneling microscopy (STM) shows that nuclei formation is limited by precursor dissociation which occurs on terraces, not at step sites. Also, the average size of clusters formed during CVD is larger than for Fe growth by evaporation (a random deposition process). Based on STM data and Monte Carlo simulations, we conclude that the CVD-growth morphology is affected by preferential dissociation of Fe(CO){sub 5} molecules at existing Fe clusters -- an autocatalytic effect. We demonstrate that nucleation kinetics can be used to control formation of metal nanostructures on chemically tailored surfaces. Reactive sites on Si (001) are first passivated by hydrogen. H atoms are locally removed by electron stimulated desorption using electrons emitted from the STM tip. Subsequent pyrolysis of Fe(CO){sub 5} leads to selective nucleation and growth of Fe films in the areas where H has been removed.
Mayer, T.M.; Adams, D.P.; Swartzentruber, B.S.; Chason, E.
Iron (III) Chloride doping of large-area chemical vapor deposition graphene
Chemical doping is an effective method of reducing the sheet resistance of graphene. This thesis aims to develop an effective method of doping large area Chemical Vapor Deposition (CVD) graphene using Iron (III) Chloride ...
Song, Yi, S.M. Massachusetts Institute of Technology
Initiated chemical vapor deposition of fluoropolymer coatings for the surface modification of complex geometries
Initiated chemical vapor deposition (iCVD) is a one-step, soventless process that can be used to produce polymeric thin films. The iCVD technique has been used to polymerize a wide variety of vinyl monomers such as glycidyl ...
Gupta, Malancha, 1980-
Vapor deposition of hardened niobium
A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.
Blocher, Jr., John M. (Columbus, OH); Veigel, Neil D. (Columbus, OH); Landrigan, Richard B. (Columbus, OH)
Codeposition on hot CVD surfaces: Particle dynamics and deposit roughness interactions
To capture in a tractable manner essential coupling effects in CVD systems when particles generated in thermal boundary layers also deposit, a film theory was developed that predicts simultaneous vapor and particle deposition rates at a hot deposition surface. The codeposition rate prediction method also calculates for the first time the corresponding solid deposit roughness using recently published results of particle-level simulations. For the numerical illustrations, the growth of TiO{sub 2}(s) films by the codeposition of titanium tetra-isopropoxide vapor and film-nucleated/grown TiO{sub 2} particles (generated in the thermal boundary layer) was considered. Experimental rate data for this system are available. The continuum and particle-level simulation methods provide: the interplay of vapor precursor kinetics, particle nucleation, growth, coagulation and diffusion in determining the complex ``structure`` of such multiphase chemically reacting boundary layers; wall deposition rates of both surviving vapors and film-nucleated particles; and the ``self-consistent`` microstructure (surface roughness) of the resulting solid deposit. Timely and tractable generalizations are discussed in the light of recent results for the transport properties and stability of ``fractal-like`` aggregated particles.
Tandon, P.; Rosner, D.E. [Yale Univ., New Haven, CT (United States)
THEORY The mass transport processes in low pressure chemical vapor deposition (LPCVD) are similar to those occuring in catalytic reactors
Gieske, R.J.
Photoluminescence in Chemical Vapor Deposited ZnS: insight into electronic defects
Photoluminescence spectra taken from chemical vapor deposited (CVD) ZnS are shown to exhibit sub-band-gap emission bands characteristic of isoelectronic oxygen defects. The emission spectra vary spatially with position and orientation with respect to the major axis of CVD growth. These data suggest that a complex set of defects exist in the band gap of CVD ZnS whose structural nature is highly dependent upon local deposition and growth conditions, contributing to inherent heterogeneity in optical behavior throughout the material.
McCloy, John S.; Potter, B.g.
Combustion chemical vapor deposited coatings for thermal barrier coating systems
The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings. In this report, the evaluation of alumina and ceria coatings on a nickel-chromium alloy is described.
Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States). School of Materials Science and Engineering
Photochemical vapor deposition of amorphous silicon photovoltaic devices. Semiannual subcontract report, 1 May 1985-31 October 1985
Intrinsic, p-type, and n-type hydrogenated amorphous silicon thin-films have been deposited by mercury-sensitized photochemical vapor deposition (photo-CVD) from disilane. The photochemical reactor design includes two chambers separated by a movable uv-transparent Teflon curtain to eliminate deposition on the reactor window. Glass/TCO/p-i-n/metal photovoltaic devices were fabricated by photo-CVD. The efficiency at 87.5 MW/cm/sup 2/(ELH) was 5.1%.
Baron, B.N.; Rocheleau, R.E.; Hegedus, S.S.
Chemical vapor deposition growth. Quarterly report No. 3
The purpose of the contract is to explore the chemical vapor deposition (CVD) method for the growth of Si sheet on inexpensive substrate materials. The work is carried out at the Rockwell Electronics Research Division in Anaheim, and also involves some experimental solar cell fabrication and evaluation by the Photo-electronics Group of Optical Coating Laboratory, Inc. (OCLI), in City of Industry, California. The contract program is composed of six main technical tasks: (1) modification and test of an existing CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures (by OCLI), using standard and near-standard processing techniques. The progress achieved during the fourth quarter is described by task, followed by a summary of conclusions and recommendations and an outline of the work planned for the next three months. The manpower and funding expenditures to date are summarized in Appendix A, and the Updated Technical Program Plan is included as Appendix B.
Ruth, R.P.; Manasevit, H.M.; Johnson, R.D.; Moudy, L.A..; Simpson, W.I.; Yang, J.J.
Chemical vapor deposition of functionalized isobenzofuran polymers
This thesis develops a platform for deposition of polymer thin films that can be further tailored by chemical surface modification. First, we explore chemical vapor deposition of functionalized isobenzofuran films using ...
Olsson, Ylva Kristina
Chemical vapor depositing of metal fluorides
High Purity BeF2 and BeF2�AlF3glasses have been deposited by the chemical vapor deposition technique using beryllium and aluminum 1
A. Sarhangi; J. M. Power
Self-catalyzed chemical vapor deposition method for the growth of device-quality metal thin films
Deposition of metals and alloys was demonstrated using thermal chemical vapor deposition starting from commercially available precursors in the absence of molecular hydrogen. The adopted chemical strategy relies solely on the selective reactivity of ... Keywords: CVD of metals, Chemical reduction, Direct liquid injection, Pulsed spray evaporation
N. Bahlawane; P. Antony Premkumar; K. Onwuka; G. Reiss; K. Kohse-H�inghaus
Chemical vapor deposition of hydrogenated amorphous silicon from disilane
The authors describe hydrogenated amorphous silicon (a-Si:H) thin films deposited at growth rates of 1 to 30 A/s by chemical vapor deposition (CVD) from disilane source gas at 24 torr total pressure in a tubular reactor. The effects of substrate temperature and gas holding time (flow rate) on film growth rate and effluent gas composition were measured at temperatures ranging from 360{sup 0} to 485{sup 0}C and gas holding times from 3 to 62s. Effluent gases determined by gas chromatography included silane, disilane and other higher order silanes. A chemical reaction engineering model, based on a silylene (SiH/sub 2/) insertion gas phase reaction network and film growth from both SiH/sub 2/ and high molecular weight silicon species, Si/sub n/H/sub 2n/, was developed. The model predictions were in good agreement with experimentally determined growth rates and effluent gas compositions.
Bogaert, R.J.; Russell, T.W.F.; Klein, M.T. (Delaware Univ., Newark, DE (USA). Dept. of Chemical Engineering); Rocheleau, R.E.; Baron, B.N. (Delaware Univ., Newark, DE (USA). Inst. of Energy Conversion)
Low-pressure chemical vapor deposition of amorphous silicon photovoltaic devices. Annual technical progress report, 1 May 1984-30 April 1985
Intrinsic and doped a-Si:H films were deposited by low pressure chemical vapor deposition (CVD) for disilane. Intrinsic layers were deposited at growth rates as high as 50 A/s. A chemical reaction engineering model that quantitatively describes the CVD reactor behavior has been developed. CVD intrinsic material was characterized by measurements of impurities, optical band gap, photoconductivity, activation energy, diffusion length, and density of states. Photovoltaic cells of the p-i-n type with efficiencies of 4% and 3.6% were fabricated using CVD intrinsic layers deposited at 1 A/s and 9 A/s, respectively. A maximum short-circuit current of 11 mA/cm/sup 2/ under 87.5 MW/cm/sup 2/ ELH illumination was obtained with boron-compensated CVD intrinsic material. Efficiency-limiting mechanisms in CVD cells were quantitatively analyzed and related to fundamental properties.
Photoinitiated chemical vapor depostion [sic] : mechanism and applications
Photoinitiated chemical vapor deposition (piCVD) is developed as a simple, solventless, and rapid method for the deposition of swellable hydrogels and functional hydrogel copolymers. Mechanistic experiments show that piCVD ...
Baxamusa, Salmaan Husain
Chemical vapor deposition of amorphous silicon films from disilane
Amorphous silicon films for fabrication of solar cells have been deposited by thermal chemical vapor deposition (CVD) from disilane (Si/sub 2/H/sub 6/) using a tubular flow reactor. A mathematical description for the CVD reactor was developed and solved by a numerical procedure. The proposed chemical reaction network for the model is based on silylene (SiH/sub 2/) insertion in the gas phase and film growth from SiH/sub 2/ and silicon polymers (Si/sub n/N/sub 2n/, n approx. 10). Estimates of the rate constants have been obtained for trisilane decomposition, silicon polymer formation, and polymer dehydrogenation. The silane unimolecular decomposition rate constants were corrected for pressure effects. The model behavior is compared to the experimental results over the range of conditions: reactor temperature (360 to 485/sup 0/C), pressures (2 to 48 torr), and gas holding time (1 to 70 s). Within the above range of conditions, film growth rate varies from 0.01 to 30 A/s. Results indicate that silicon polymers are the main film precursors for gas holding times greater than 3 s. Film growth by silylene only becomes important at short holding times, large inert gas dilution, and positions near the beginning of the reactor hot zone.
Bogaert, R.J.
Comparison between chemical vapor deposited and physical vapor deposited WSi{sub 2} metal gate for InGaAs n-metal-oxide-semiconductor field-effect transistors
We compare chemical vapor deposition (CVD) and physical vapor deposition (PVD) WSi{sub 2} metal gate process for In{sub 0.53}Ga{sub 0.47}As n-metal-oxide-semiconductor field-effect transistors using 10 and 6.5 nm Al{sub 2}O{sub 3} as dielectric layer. The CVD-processed metal gate device with 6.5 nm Al{sub 2}O{sub 3} shows enhanced transistor performance such as drive current, maximum transconductance and maximum effective mobility. These values are relatively better than the PVD-processed counterpart device with improvement of 51.8%, 46.4%, and 47.8%, respectively. The improvement for the performance of the CVD-processed metal gate device is due to the fluorine passivation at the oxide/semiconductor interface and a nondestructive deposition process.
Ong, B. S.; Pey, K. L. [Advanced Materials for Micro and Nano-Systems, Singapore-MIT Alliance, Singapore 637460 (Singapore); School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Ong, C. Y.; Tan, C. S. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Antoniadis, D. A. [Advanced Materials for Micro and Nano-Systems, Singapore-MIT Alliance, Singapore 637460 (Singapore); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Fitzgerald, E. A. [Advanced Materials for Micro and Nano-Systems, Singapore-MIT Alliance, Singapore 637460 (Singapore); Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
High rate chemical vapor deposition of carbon films using fluorinated gases
A high rate, low temperature deposition of amorphous carbon films is produced by PE-CVD in the presence of a fluorinated or other halide gas. The deposition can be 5 performed at less than 100C, including ambient room temperature, with a radio frequency plasma assisted chemical vapor deposition process. With less than 6.5 at% fluorine incorporated into the amorphous carbon film, the characteristics of the carbon film, including index of 10 refraction, mass density, optical clarity, and chemical resistance are within 15% of those characteristics for pure amorphous carbon films, but the deposition rates are high.
Stafford, B.L.; Tracy, C.E.; Benson, D.K.; Nelson, A.J.
A high rate, low-temperature deposition of amorphous carbon films is produced by PE-CVD in the presence of a fluorinated or other halide gas. The deposition can be performed at less than 100.degree. C., including ambient room temperature, with a radio frequency plasma assisted chemical vapor deposition process. With less than 6.5 atomic percent fluorine incorporated into the amorphous carbon film, the characteristics of the carbon film, including index of refraction, mass density, optical clarity, and chemical resistance are within fifteen percent (15%) of those characteristics for pure amorphous carbon films, but the deposition rates are high.
Stafford, Byron L. (Arvada, CO); Tracy, C. Edwin (Golden, CO); Benson, David K. (Golden, CO); Nelson, Arthur J. (Longmont, CO)
Low Temperature Chemical Vapor Deposition Of Thin Film Magnets
A thin-film magnet formed from a gas-phase reaction of tetracyanoetheylene (TCNE) OR (TCNQ), 7,7,8,8-tetracyano-P-quinodimethane, and a vanadium-containing compound such as vanadium hexcarbonyl (V(CO).sub.6) and bis(benzene)vanalium (V(C.sub.6 H.sub.6).sub.2) and a process of forming a magnetic thin film upon at least one substrate by chemical vapor deposition (CVD) at a process temperature not exceeding approximately 90.degree. C. and in the absence of a solvent. The magnetic thin film is particularly suitable for being disposed upon rigid or flexible substrates at temperatures in the range of 40.degree. C. and 70.degree. C. The present invention exhibits air-stable characteristics and qualities and is particularly suitable for providing being disposed upon a wide variety of substrates.
Miller, Joel S. (Salt Lake City, UT); Pokhodnya, Kostyantyn I. (Salt Lake City, UT)
Hydrogenated amorphous silicon films produced by chemical vapor deposition: Final report
Hydrogenated amorphous silicon (a-Si:H) is a technologically important semiconductor, well-suited for solar photovoltaic energy conversion and thin film device applications. While the glow discharge technique is widely used for the deposition of a-Si:H films, this work is focused on the use of the chemical vapor deposition (CVD) technique, i.e., the thermal decomposition of disilane and higher silanes, for the deposition of a-Si:H films. A simple technique for the preparation of disilane and higher silanes by using an electric discharge in monosilane under atmospheric pressure has been developed, and the discharge product can be used directly for the deposition process. The important parameters of the CVD process including the substrate temperature, the composition and flow rate of the reaction mixture, and the nature of the diluent gas for disilane, have also been investigated. The deposition rate of a-Si:H films in a helium atmosphere is considerably higher than that in a hydrogen atmosphere, and the CVD process in a helium atmosphere is well-suited for the deposition of thick a-Si:H films. The a-Si:H films deposited under various conditions have been characterized by the photoconductivity, dissolution rate, optical absorption, mechanical stress, gap state density, minority carrier diffusion length, and stability measurements. On the basis of these measurements, a-Si:H films deposited by the thermal decomposition of disilane in a helium atmosphere exhibit better structural and electronic properties than those deposited in a hydrogen atmosphere.
Not Available
Photochemical vapor deposition of amorphous silicon photovoltaic devices: Annual subcontract report, 1 May 1985-30 April 1986
Intrinsic, p-type, and n-type a-Si:H and p-type a-SiC:H thin-films have been deposited by Hg-sensitized photochemical vapor depositions (photo-CVD) from disilane. The photochemical reactor design includes two chambers separated by a movable uv-transparent Teflon curtain, which eliminates deposition on the reactor window. Photovoltaic devices of the type glass/TCO/p-i-n/metal were fabricated by photo-CVD. The device efficiency obtained at 87.5 mW/cm/sup 2/ and ELH illumination was 6.4%.
Effect of e-beam irradiation on graphene layer grown by chemical vapor deposition
We have grown graphene by chemical vapor deposition (CVD) and transferred it onto Si/SiO{sub 2} substrates to make tens of micron scale devices for Raman spectroscopy study. The effect of electron beam (e-beam) irradiation of various doses (600 to 12 000 {mu}C/cm{sup 2}) on CVD grown graphene has been examined by using Raman spectroscopy. It is found that the radiation exposures result in the appearance of the strong disorder D band attributed the damage to the lattice. The evolution of peak frequencies, intensities, and widths of the main Raman bands of CVD graphene is analyzed as a function of defect created by e-beam irradiation. Especially, the D and G peak evolution with increasing radiation dose follows the amorphization trajectory, which suggests transformation of graphene to the nanocrystalline and then to amorphous form. We have also estimated the strain induced by e-beam irradiation in CVD graphene. These results obtained for CVD graphene are in line with previous findings reported for the mechanically exfoliated graphene [D. Teweldebrhan and A. A. Balandin, Appl. Phys. Lett. 94, 013101 (2009)]. The results have important implications for CVD graphene characterization and device fabrication, which rely on the electron microscopy.
Iqbal, M. Z.; Kumar Singh, Arun; Iqbal, M. W.; Seo, Sunae; Eom, Jonghwa [Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747 (Korea, Republic of)
Microwave plasma chemical vapor deposition of nano-composite...
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plasma chemical vapor deposition of nano-composite CPt thin-films Title Microwave plasma chemical vapor deposition of nano-composite CPt thin-films Publication Type Journal...
Chemical vapor deposition of amorphous semiconductor films. Semiannual report, 1 May 1984-31 October 1984
This report describes the results of research done by the Institute of Energy Conversion for the Solar Energy Research Institute in 1984 on high-efficiency, stable, amorphous silicon solar cells, fabricated by chemical vapor deposition (CVD) from disilane at high growth rates. The kinetics of CVD with higher order silanes were modelled for a tubular reactor with static substrates. A gas-phase reaction network was adopted, based on published silylene insertion and decomposition pathways. Mass balances for hydrogen and all saturated silanes through octasilane were derived. Boron-doped a-Si:H p-layers were deposited by CVD at 200/sup 0/ to 250/sup 0/C. Band gap and conductivity depended strongly on the diborane fraction in the feed gas, independent of substrate temperature. The effects of intrinsic layer deposition temperature and growth rate on material properties and device performance were studied. Cell parameters of p-i-n cells were correlated with i-layer deposition temperature and growth rate. Fill factor and short-circuit current depended on deposition conditions, while open-circuit voltage did not. Effects of diborane additions to the feed gas during i-layer deposition were studied. Experimental evidence and calculations indicate high resistance at the back contact.
Apparatus and method for photochemical vapor deposition
A photochemical vapor deposition apparatus includes a reactor housing having a window in one wall above a reaction chamber in the housing. A transparent curtain divides the reaction chamber into a reaction zone and a flush zone. At least one substrate is mounted in the reaction zone in light communication with the window so that ultraviolet radiation may penetrate through the window into the reaction zone. The window is kept clear by a gas flowing through the flush zone.
Jackson, Scott C. (Wilmington, DE); Rocheleau, Richard E. (Wilmington, DE)
A molecular view of vapor deposited glasses
Recently, novel organic glassy materials that exhibit remarkable stability have been prepared by vapor deposition. The thermophysical properties of these new ''stable'' glasses are equivalent to those that common glasses would exhibit after aging over periods lasting thousands of years. The origin of such enhanced stability has been elusive; in the absence of detailed models, past studies have discussed the formation of new polyamorphs or that of nanocrystals to explain the observed behavior. In this work, an atomistic molecular model of trehalose, a disaccharide of glucose, is used to examine the properties of vapor-deposited stable glasses. Consistent with experiment, the model predicts the formation of stable glasses having a higher density, a lower enthalpy, and higher onset temperatures than those of the corresponding ''ordinary'' glass formed by quenching the bulk liquid. Simulations reveal that newly formed layers of the growing vapor-deposited film exhibit greater mobility than the remainder of the material, thereby enabling a reorganization of the film as it is grown. They also reveal that ''stable'' glasses exhibit a distinct layered structure in the direction normal to the substrate that is responsible for their unusual properties.
Singh, Sadanand; Pablo, Juan J. de [Department of Chemical and Biological Engineering, University of Wisconsin, Madison Wisconsin 53706 (United States)
Amorphous silicon photovoltaic devices prepared by chemical and photochemical vapor deposition of higher order silanes. Technical progress report, 1 September 1984-28 February 1985
This report describes the preparation of hydrogenated amorphous silicon (a-Si:H) films and photovoltaic devices by chemical vapor deposition (CVD) from higher order silanes, and the properties of such films and devices. The research is directed at exploring new, improved deposition techniques to produce a-Si:H. The improvement could stem from ease of deposition (lower cost and/or better reproducibility), from material improvement (higher efficiency and/or better stability under illumination), or from innovative materials that improve device performance. Research efforts have focused, therefore, on photo-CVD techniques; thermal CVD has been emphasized. This report summarizes the properties of the experimental thermal CVD films and the reasons for terminating the research in this area. In addition, the results for deposition by mercury-sensitized decomposition of disilane are presented. These results indicate that this technique is a very promising alternative to the glow-discharge method.
Delahoy, A.E.; Ellis, F.B. Jr.
a-Si:H Grown by Hot-Wire CVD at Ultra-High Deposition Rates
We increase the deposition rate of growing hydrogenated amorphous-silicon (a-Si:H) by the hot-wire chemical vapor depositon (HWCVD) technique by adding filaments (two) and decreasing the filament(s) to substrate distance.
Xu, Y.; Nelson, B. P.; Mahan, A. H.; Williamson, D. L.; Crandall, R. S.; Iwaniczko, E.; Wang, Q.
Low Temperature Direct Growth of Graphene Films on Transparent Substrates by Chemical Vapor Deposition
and Few- Layer Graphene by Chemical Vapor Deposition",Liu, W. , et al. (2010). "Chemical vapor deposition of large5 1.3.3. Chemical Vapor
Antoine, Geoffrey Sandosh Jeffy
In-situ deposition of high-k dielectrics on III-V compound semiconductor in MOCVD system
In situ deposition of high-k materials to passivate the GaAs in metal organic chemical vapor deposition (MOCVD) system was well demonstrated. Both atomic layer deposition (ALD) and chemical vapor deposition (CVD) methods ...
Cheng, Cheng-Wei, Ph.D. Massachusetts Institute of Technology
Chemical Vapor Deposition of Silicon Carbide Epitaxial Films and their Characterization
A chemical vapor deposition (CVD) system was designed and fabricated in our laboratory and SiC homo-epitaxial layers were grown in the CVD process using silicon tetrachloride and propane precursors with hydrogen as a carrier gas. The temperature field was generated using numerical modeling. Gas flow rates, temperature field, and the gradients are found to influence the growth rates of the epitaxial layers. Growth rates were found to increase as the temperature increased at high carrier gas flow rate, while at lower carrier gas flow rate, growth rates were observed to decrease as the temperature increased. Based on the equilibrium model, 'thermodynamically controlled growth' accounts for the growth rate reduction. The grown epitaxial layers were characterized using various techniques. Reduction in the threading screw dislocation (SD) density in the epilayers was observed. Suitable models were developed for explaining the reduction in the SD density as well as the conversion of basal plane dislocations (BPDs) into threading edge dislocations (TEDs).
Dhanaraj,G.; Chen, Y.; Dudley, M.; Cai, D.; Zhang, H.
Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications
Diamond was studied as a possible radiation hard technology for use in future high radiation environments. With the commissioning of the LHC expected in 2010, and the LHC upgrades expected in 2015, all LHC experiments are planning for detector upgrades which require radiation hard technologies. Chemical Vapor Deposition (CVD) diamond has now been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle and CDF and is installed and operational in all LHC experiments. As a result, this material is now being discussed as an alternative sensor material for tracking very close to the interaction region of the super-LHC where the most extreme radiation conditions will exist. Our work addressed the further development of the new material, single-crystal Chemical Vapor Deposition diamond, towards reliable industrial production of large pieces and new geometries needed for detector applications.
Rainer Wallny
Metal film deposition by laser breakdown chemical vapor deposition
Dielectric breakdown of gas mixtures can be used to deposit homogeneous thin films by chemical vapor deposition with appropriate control of flow and pressure conditions to suppress gas phase nucleation and particle formation. Using a pulsed CO/sub 2/ laser operating at 10.6 microns where there is no significant resonant absorption in any of the source gases, we have succeeded in depositing homogeneous films from several gas phase precursors by gas phase laser pyrolysis. Nickel and molybdenum from the respective carbonyls and tungsten from the hexafluoride have been examined to date. In each case the gas precursor is buffered to reduce the partial pressure of the reactants and to induce breakdown. The films are spectrally reflective and uniform over a large area. Films have been characterized by Auger electron spectroscopy, x-ray diffraction, pull tests, and resistivity measurements. The highest quality films have resulted from the nickel depositions. Detailed x-ray diffraction analysis of these films yields a very small domain size (approx. 50 A) consistent with rapid quenching from the gas phase reaction zone. This analysis also shows nickel carbide formation consistent with the temperature of the reaction zone and the Auger electron spectroscopy results which show some carbon and oxygen incorporation (8% and 1% respectively). Gas phase transport and condensation of the molybdenum carbonyl results in substantial carbon and oxygen contamination of the molybdenum films requiring heated substrates, a requirement not consistent with the goals of the program to maximize the quench rate of the deposition. Results from tungsten deposition experiments representing a reduction chemistry instead of the decomposition chemistry involved in the carbonyl experiments are also reported.
Jervis, T.R.
Amorphous silicon photovoltaic devices prepared by chemical and photochemical vapor deposition of higher order silanes. Annual subcontract progress report, 1 September 1984-31 August 1985
This report describes the preparation of hydrogenated amorphous silicon (a-Si:H) films and photovoltaic devices by chemical vapor deposition (CVD) from higher order silanes and the properties of such films and devices. The research explored new deposition techniques that could produce a-Si:H superior to that achieved by the glow-discharge method. For example, the improvement could stem from ease of deposition (lower cost and/or better reproducibility), from material improvement (higher efficiency and/or better stability under illumination), or from innovative materials that improve device performance. Research focused on photo-CVD techniques; thermal CVD deemphasized. This report presents results for deposition by mercury-sensitized decomposition of disilane. These results indicate that this technique is a very promising alternative to the glow-discharge method.
Wide-Gap Thin Film Si n-i-p Solar Cells Deposited by Hot-Wire CVD: Preprint
High-voltage wide bandgap thin-film Si n-i-p solar cells have been made using the hot-wire chemical vapor deposition (HWCVD) technique. The best open-circuit voltage (Voc) has exceeded 0.94 V in solar cells using HWCVD in the entire n-i-p structure. A Voc of 0.97V has been achieved using HWCVD in the n and i layers and plasma-enhanced (PE) CVD for the p layer. The high voltages are attributed to the wide-gap i layer and an improved p/i interface. The wide-gap i layer is obtained by using low substrate temperatures and sufficient hydrogen dilution during the growth of the i layer to arrive at the amorphous-to-microcrystalline phase transition region. The optical band gap (E04) of the i layer is found to be 1.90 eV. These high-voltage cells also exhibit good fill factors exceeding 0.7 with short-circuit-current densities of 8 to 10 mA/cm2 on bare stainless steel substrates. We have also carried out photoluminescence (PL) spectroscopy studies and found a correlation between Voc and the PL peak energy position.
Wang, Q.; Iwaniczko, E.; Yang, J.; Lord, K.; Guha, S.; Wang, K.; Han, D.
Photochemical vapor deposition of undoped and n-type amorphous silicon films produced from disilane
Hydrogenated amorphous silicon films have been deposited by mercury photosensitized decomposition (photochemical vapor deposition: photo-CVD) of disilane at a substrate temperature below 300 /sup 0/C. The structural and optical properties of undoped films are very similar to those of films deposited by rf glow discharge decomposition. The electronic property measurement shows that the conductivity strongly depends on the substrate temperature during deposition. The photoconductivity reaches 5.7 x 10/sup -3/ (..cap omega.. cm)/sup -1/ (AM1,100 mW/cm/sup 2/) at a substrate temperature of 200 /sup 0/C. The dark conductivity is 10/sup -6/--10/sup -8/ (..cap omega.. cm)/sup -1/ and the Fermi level is located near the middle of the gap. n-type doping has been also achieved by adding phosphine as an impurity to disilane. Furthermore, a p-i-n a-Si solar cell was fabricated using photo-CVD undoped and P-doped films. The initial cell showed a conversion efficiency of 4.39% under AM1 insolation.
Inoue, T.; Konagai, M.; Takahashi, K.
Aspects of nitrogen surface chemistry relevant to TiN chemical vapor deposition
NH{sub 3} is an important component of many chemical vapor deposition (CVD) processes for TiN films, which are used for diffusion barriers and other applications in microelectronic circuits. In this study, the interaction of NH{sub 3} with TiN surfaces is examined with temperature programmed desorption (TPD) and Auger electron spectroscopy. NH{sub 3} has two adsorption states on TiN: a chemisorbed state and a multilayer state. A new method for analyzing TPD spectra in systems with slow pumping speeds yields activation energies for desorption for the two states of 24 kcal/mol and 7.3 kcal/mol, respectively. The sticking probability into the chemisorption state is {approximately}0.06. These results are discussed in the context of TiN CVD. In addition, the high temperature stability of TiN is investigated. TiN decomposes to its elements only after heating to 1300 K, showing that decomposition is unlikely to occur under CVD conditions.
Schulberg, M.T.; Allendorf, M.D.; Outka, D.A.
Chemical vapor deposition growth. Annual report
The formal objective of the contract is development of CVD techniques for producing large areas of Si sheet on inexpensive substrate materials, with sheet properties suitable for fabricating solar cells. The techniques developed are to be directed toward (1) minimum-cost processing, (2) production of sheet having properties adequate to result in cells with terrestrial array efficiency of 10 percent or more, and (3) eventual scale-up to large-quantity production. (WDM)
Ruth, R.P.; Manasevit, H.M.; Johnson, R.E.; Kenty, J.L.; Moudy, L.A.; Simpson, W.I.; Yang, J.J.
Chemical vapor deposition growth. Quarterly report No. 1
The activities of the first quarter of the contract, which began December 29, 1975, are described. An existing laboratory-type CVD reactor system with a vertical deposition chamber has been used for growth of the Si films studied to date. Extensive modifications of this system, involving mass flow controllers and automatic timing of reactant gas flows by means of solenoid-activated air-operated bellows valves, will be completed early in the second quarter. (WDM)
Ruth, R.P.; Manasevit, H.M.; Kenty, J.L.; Moudy, L.A.; Simpson, W.I.; Yang, J.J.
Diameter tuning of single-walled carbon nanotubes by diffusion plasma CVD
We have realized a diameter tuning of single-walled carbon nanotubes (SWNTs) by adjusting process gas pressures with plasma chemical vapor deposition (CVD). Detailed photoluminescence measurements reveal that the diameter distribution of SWNTs clearly ...
Toshiaki Kato; Shunsuke Kuroda; Rikizo Hatakeyama
Low temperature plasma enhanced chemical vapor deposition of silicon oxide films using disilane and nitrous oxide
Keywords: disilane, low temperature, nitrous oxide, plasma enhanced chemical vapor deposition, silicon oxide
Juho Song; G. S. Lee; P. K. Ajmera
Chemical vapor deposition thin films as biopassivation coatings and directly patternable dielectrics
Organosilicon thin films deposited by pulsed plasma-enhanced chemical vapor deposition (PPECVD) and hot-filament chemical vapor deposition (HFCVD) were investigated as potential biopassivation coatings for neural probes. ...
Pryce Lewis, Hilton G. (Hilton Gavin), 1973-
CAT-CVD process and its application to preparation of Si-based thin films
This is to review the present understanding on Cat-CVD (catalytic chemical vapor deposition) or hot wire CVD. Firstly, the deposition mechanism in Cat-CVD process is briefly mentioned along with key issues such as the effect of heat radiation and a method to avoid contamination from the catalyzer. Secondly, the properties of Cat-CVD Si-based thin films such as amorphous silicon (a-Si), polycrystalline silicon (poly-Si) and silicon nitride (SiN{sub x}) films are demonstrated, and finally, the feasibility of such films for industrial application is discussed.
Matsumura, Hideki; Masuda, Atsushi; Izumi, Akira
Tunable Raman spectroscopy study of CVD and peapod-derived bundled and individual double-wall carbon nanotubes
We use 40 laser excitation energies to analyze the differences in the Raman spectra from chemical vapor deposition-derived double-wall carbon nanotube (CVD-DWNT) bundles, fullerene-derived DWNT bundles (C[subscript 60]-DWNTs), ...
Dresselhaus, Mildred
Atmospheric-Pressure Chemical Vapor Deposition of Iron Pyrite Thin Films
Iron pyrite (cubic FeS{sub 2}) is a promising candidate absorber material for earth-abundant thin-film solar cells. In this report, single-phase, large-grain, and uniform polycrystalline pyrite thin films are fabricated on glass and molybdenum-coated glass substrates by atmospheric-pressure chemical vapor deposition (AP-CVD) using the reaction of iron(III) acetylacetonate and tert-butyl disulfide in argon at 300 C, followed by sulfur annealing at 500--550 C to convert marcasite impurities to pyrite. The pyrite-marcasite phase composition depends strongly on the concentration of sodium in the growth substrate and the sulfur partial pressure during annealing. Phase and elemental composition of the films are characterized by X-ray diffraction, Raman spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, Rutherford backscattering spectrometry, and X-ray photoelectron spectroscopy. The in-plane electrical properties are surprisingly insensitive to phase and elemental impurities, with all films showing p-type, thermally activated transport with a small activation energy ({approx}30 meV), a room- temperature resistivity of {approx}1 {Omega} cm, and low mobility. These ubiquitous electrical properties may result from robust surface effects. These CVD pyrite thin films are well suited to fundamental electrical studies and the fabrication of pyrite photovoltaic device stacks.
Berry, Nicholas; Cheng, Ming; Perkins, Craig L.; Limpinsel, Moritz; Hemminger, John C.; Law, Matt (NREL); (UCI)
Impact of hydrogen and oxygen defects on the lattice parameter of chemical vapor deposited zinc sulfide
The lattice parameter of cubic chemical vapor deposited (CVD) ZnS with measured oxygen concentrations < 0.6 at.% and hydrogen impurities of < 0.015 at.% have been measured and found to vary between -0.10% and +0.09% relative to the reference lattice parameter (5.4093 �) of oxygen-free cubic ZnS as reported in the literature. Defects other than substitutional O must be invoked to explain these observed volume changes. The structure and thermodynamic stability of a wide range of native and impurity induced defects in ZnS have been determined by Ab initio calculations. Lattice contraction is caused by S-vacancies, substitutional O on S sites, Zn vacancies, H in S vacancies, peroxy defects, and dissociated water in S-vacancies. The lattice is expanded by interstitial H, H in Zn vacancies, dihydroxy defects, interstitial oxygen, Zn and [ZnHn] complexes (n=1,�,4), interstitial Zn, and S2 dumbbells. Oxygen, though present, likely forms substitutional defects for sulfur resulting in lattice contraction rather than as interstitial oxygen resulting in lattice expansion. It is concluded based on measurement and calculations that excess zinc atoms either at anti-sites (i.e. Zn atoms on S-sites) or possibly as interstitial Zn are responsible for the relative increase of the lattice parameter of commercially produced CVD ZnS.
McCloy, John S.; Wolf, Walter; Wimmer, Erich; Zelinski, Brian
Fabrication of solid oxide fuel cell by electrochemical vapor deposition
In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (approximately 1100.degree.-1300.degree. C.) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20-50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.
Brian, Riley (Willimantic, CT); Szreders, Bernard E. (Oakdale, CT)
In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (/approximately/1100/degree/ /minus/ 1300/degree/C) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20--50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.
Riley, B.; Szreders, B.E.
Low-band-gap, amorphous-silicon-based alloys by chemical vapor deposition: Annual subcontract report, 1 October 1985-31 January 1986
This research was conducted to determine the potential of photochemical vapor deposition (photo-CVD) for producing high-quality, low-band-gap amorphous silicon germanium alloys for use in high-efficiency, multijunction, thin-film photovoltaic solar cells. A photo-CVD reactor for mercury-sensitized photolysis of silane-germane and disilane-germane mixtures was developed. Alloy thin films of undoped a-Si/sub 1-x/Ge/sub x/:H were deposited using mercury vapor mixed with SiH/sub 4/ or Si/sub 2/H/sub 6/, GeH/sub 4/, and diluent gas of Ar, He, or H/sub 2/. Materials properties were characterized by measurements of Ge content, optical transmission and reflection, and dark and photo-conductivity. Opto-electronic properties of photo-CVD a-Si/sub 1-x/Ge/sub x/:H were found to be comparable to glow discharge and sputtered materials. Moreover, p-i-n solar cells with low-band-gap i-layers were able to be fabricated by photo-CVD.
Baron, B.N.; Jackson, S.C.
Physical vapor deposition and patterning of calcium fluoride films
Physical vapor deposition of calcium fluoride (CaF{sub 2}) thin films was performed via electron beam evaporation, resistive/thermal evaporation, and nonreactive radio frequency sputtering. Patterning of the resultant ''usable'' thin films was then also attempted in several ways, including by shadow mask deposition, liftoff, and direct chemical etching. Resistive evaporation produced the most stable films, having polycrystalline morphology with a moderately strong preference to the 331 orientation. The cleanest patterning results were obtained via a polymer/metal liftoff. The results and implications of each of the various deposition and patterning techniques are discussed.
Pinol, L.; Rebello, K.; Caruso, K.; Francomacaro, A. S.; Coles, G. L. [Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland 20723 (United States)
Environmentally focused patterning and processing of polymer thin films by initiated chemical vapor deposition (iCVD) and oxidative chemical vapor deposition (oCVD)
The new millennium has brought fourth many technological innovations made possible by the advancement of high speed integrated circuits. The materials and energy requirements for a microchip is orders of magnitude higher ...
Trujillo, Nathan J. (Nathan Jeffrey)
Chemical vapor deposition growth. Quarterly report No. 4
The contract activities during the quarter were concentrated in the following areas: (1) preparation of polished substrates of three new experimental glasses received in raw billet form from the manufacturer; (2) exploratory Si CVD growth on two experimental glazes (on aluminas), at temperatures below and above the softening points; (3) evaluation of several different surface cleaning procedures for glass substrates, with a procedure involving an acid-cleaning step being adopted as standard; (4) determination of Si film crystallographic properties on glasses (and sapphire) as a function of deposition temperature and thickness in three different thickness ranges; (5) determination of the effect of HCl additions to SiH/sub 4/ on the net growth rates and the properties of Si films grown by a two-step process at two different deposition temperatures; (6) investigation of the reproducibility of Si film growth rates when the SiH/sub 4/ flow rate is controlled by a) the mass-flow controller and b) the conventional rotameter; (7) determination of further carrier density vs added dopant concentration data for B-doped Si films grown in He at low temperatures (approximately 850/sup 0/C); (8) preparation of p-type B-doped Si films in a range of carrier densities on substrates of single-crystal Si, sapphire, and several glasses for fabrication of experimental solar cell structures; (9) preparation of p/p/sup +/ films on substrates of sapphire and single-crystal Si for solar cell fabrication; (10) evaluation of the electrical properties of the various films prepared; and (11) fabrication and characterization of experimental cells made by P diffusion into the p-type and the p/p/sup +/ CVD layers.
Ruth, R.P.; Manasevit, H.M.; Campbell, A.G.; Johnson, R.E.; Moudy, L.A.; Shaw, G.L.; Simpson, W.I.
Rapid tooling by electron-beam vapor deposition
Electron-beam physical vapor deposition (EBPVD) of tooling metal, onto a shaped substrate to produce a replica of the substrate surface, offers the potential for significant cost savings over present methods of injection mold manufacturing. These savings are realized by the high deposition rate and the corresponding short manufacturing times provided by the EBPVD process. However, on route to realizing these gains, there are process technical issues which need to be resolved. Mold surfaces typically contain relatively high aspect ratio details that must be replicated to dimensional tolerances within +/- 2 mils. The deposited mold material must also provide high surface hardness and high fracture toughness. Good quality grain structure can be obtained in deposited Al 10-wt% Cu mold material when the substrate and corresponding deposit are at high process temperature. However, the resulting mold is subject to distortion during cooldown due to differential temperatures and shrinkage rates. Thermally controlled cooldown and the use of crushable substrate materials reduce these distortions, but not to the required levels of tolerance. Deposition of the Al-Cu at lower temperature produces columnar, poorly joined grains which result in a brittle and weakened mold material. When Al 10-wt% Cu metal vapor is deposited across high aspect ratio step features on the substrate surface, a grain growth defect can form in the step-shadowed regions of the deposited material, alongside the step feature. The step coverage defect consists of entrained voids which persist at intermediate deposition temperatures and produce a weakened mold. This final 1997 LDRD report investigates causes of this step coverage defect and offers methods for their control and elimination.
Meier, T. C., LLNL
Low Temperature Chemical Vapor Deposition of Zirconium Nitride in a Fluidized Bed
The objective of this research was to design, assemble, and demonstrate the initial performance of a fluidized bed chemical vapor deposition (FB-CVD) system capable of producing thin, uniform zirconium nitride (ZrN) coatings (1 to 10 micrometers thick) on uranium-molybdenum (UMo) particulate fuel. Plate-type fuel with U-xMo (x = 3 to 10 wt.%) particle fuel dispersed in an aluminum matrix is under development at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. Initial irradiation tests performed at INL in the Advanced Test Reactor (ATR) indicate an interaction layer forms between the fuel microspheres and the matrix at relatively high power levels. These power levels induce higher temperatures which enables uranium diffusion into the aluminum during irradiation, eventually causing fuel plate failure. The objective of this work was to create a process to mitigate the fuel/matrix interaction by forming a thin barrier coating on the surface of the U-xMo microspheres before incorporation into the dispersion fuel plate matrix. One of the main challenges in performance of the FB-CVD system was the effective fluidization of a powder whose physical characteristics (size, density) are continuously changing. To address this, two types of fluidized bed reaction vessels were designed and improved over the course of this research: a spouted fluidized bed and an inverted fluidized bed. Both reaction vessels utilized tetrakis(dimethylamino)zirconium (TDMAZ) and ammonia gas as precursors at atmospheric pressure. Tungsten wires and zirconia-silica (ZrO2-SiO2) microspheres were used as the substrates for the coating experiments. The substrate temperature and precursor gas flow were manipulated as the process variables. The FB-CVD system was successful in forming zirconium based coatings on surrogate microspheres with elevated levels of chemical impurities. At atmospheric pressure, coatings of thicknesses ranging from 0.5 micrometers to 1.5 micrometers were produced between temperatures of 250 degrees C and 350 degrees C. The deposited coatings were characterized using scanning electron microscopy, energy dispersive spectroscopy and wavelength dispersive spectroscopy.
Arrieta, Marie
Method of physical vapor deposition of metal oxides on semiconductors
A process for growing a metal oxide thin film upon a semiconductor surface with a physical vapor deposition technique in a high-vacuum environment and a structure formed with the process involves the steps of heating the semiconductor surface and introducing hydrogen gas into the high-vacuum environment to develop conditions at the semiconductor surface which are favorable for growing the desired metal oxide upon the semiconductor surface yet is unfavorable for the formation of any native oxides upon the semiconductor. More specifically, the temperature of the semiconductor surface and the ratio of hydrogen partial pressure to water pressure within the vacuum environment are high enough to render the formation of native oxides on the semiconductor surface thermodynamically unstable yet are not so high that the formation of the desired metal oxide on the semiconductor surface is thermodynamically unstable. Having established these conditions, constituent atoms of the metal oxide to be deposited upon the semiconductor surface are directed toward the surface of the semiconductor by a physical vapor deposition technique so that the atoms come to rest upon the semiconductor surface as a thin film of metal oxide with no native oxide at the semiconductor surface/thin film interface. An example of a structure formed by this method includes an epitaxial thin film of (001)-oriented CeO.sub.2 overlying a substrate of (001) Ge.
Norton, David P. (Knoxville, TN)
Characteristics of indium oxide plasma filters deposited by atmospheric pressure CVD
Thin films of undoped and tin-doped In{sub 2}O{sub 3} are being investigated for use as plasma filters in spectral control applications for thermal photovoltaic cells. These films are required to exhibit high reflectance at wavelengths longer than the plasma wavelength {lambda}{sub p}, high transmittance at wavelengths shorter than {lambda}{sub p} and low absorption throughout the spectrum. Both types of films were grown via atmospheric pressure chemical vapor deposition (APCVD) on Si (100) and fused silica substrates using trimethylindium (TMI), tetraethyltin (TET), and oxygen as the precursors. Fourier Transform InfraRed (FTIR) spectroscopy was used to measure the filter transmittance and reflectance between 1.8--20 {micro}m. Nominal conditions used during the growth of undoped In{sub 2}O{sub 3} were a substrate temperature of 450 C and partial pressures of 1.4 {times} 10{sup {minus}4} atm. and 1 {times} 10{sup {minus}3} atm. for TMI and O{sub 2} respectively. The O{sub 2}/TMI partial pressure ratio and substrate temperature were systematically varied to control the filter characteristics. The plasma wavelength {lambda}{sub p} was found to be a sensitive function of these parameters. Post-growth annealing of the films was done in inert as well as air ambient at elevated temperatures, but was found to have no beneficial effect. Tin-doped In{sub 2}O{sub 3} was grown under similar conditions as above, with a typical TET partial pressure of 4 {times} 10{sup {minus}6} atm. Here also, the material properties and consequently the optical response were found to be strongly dependent on growth conditions such as O{sub 2} and TET partial pressures. Both undoped and tin-doped In{sub 2}O{sub 3} grown on fused silica exhibited enhanced transmittance due to the close matching of refractive indices of In{sub 2}O{sub 3} and silica. X-ray diffractometer measurements indicated that all these films were polycrystalline and highly textured towards the (111) direction. The best undoped and tin-doped In{sub 2}O{sub 3} films had a {lambda}{sub p} around 2.7 {micro}m, peak reflectance greater than 75% and residual absorption below 20%. These results indicate the promise of undoped and tin-doped In{sub 2}O{sub 3} as a material for plasma filters.
Langlois, E.; Murthy, S.D.; Bhat, I.; Gutmann, R. [Rensselaer Polytechnic Inst., Troy, NY (United States); Brown, E.; Dziendziel, R.; Freeman, M.; Choudhury, N. [Lockheed Martin Corp., Schenectady, NY (United States)
Results are summarized for an investigation of the sorption rates of gases on vapor-deposited titanium films. The usefulness of such films for ultrahigh speed vacuum pumping is appraised. The sorption of hydrogen, deuterium, oxygen, nitrogen, carbon monoxide, carbon dioxide, water vapor, helium, argon, and methane onto titanium films was measured for a variety of circumstances using techniques and apparatus developed for this specific purpose. The information obtained and techniques evolved in this study have shown that large-scale getter pumping is feasible and can be a very effective means of pumping many gases. Sticking fractions larger than 0.8 were obtained for hydrogen, deuterium, oxygen, nitrogen, carbon monoxide, and carbon dioxide. The experiments have shown that the sticking fraction for gases on vapor-deposited films is a function of the deposition conditions. There is strong evidence to support the supposition that conditions which favor the formation of a porous, fine-grained film structure with a large surface-to-volume ratio produce films with the highest sorption rates. The technique for measuring sticking fractions is new and in many respects unique. It utilizes a very large sorption surface, thus minimizing the perturbing effect of the instrumentation and evaporation apparatus and reducing the hazard of film contamination due to small leaks in the system or outgassing of system components. The method gives especially good accuracy for measurements of sticking fractions approaching unity. The quantity of gas adsorbed, the gas flux onto the getter surface, and the gas flux leaving the getter surface are measured directly. Any two of these three independent measurements can be used to determine the sticking fraction, thereby providing a means of checking the data. The evaporation techniques, substrate surface, and substrate area were chosen to very nearly duplicate the conditions likely to be encountered in the practical application of large-scale getter pumping. (auth)
Clausing, R.E.
Abstract--Selective epitaxial growth of crystalline Ge on Si in a standard ASM Epsilon 2000 CVD reactor is investigated for the
In a standard CVD reactor, Ge selective epitaxial growth on patterned Si substrates was developed in thickness. The epitaxy is performed in a standard ASM Epsilon 2000 chemical-vapor-deposition (CVD) reactor surface after Ge-growth make this an attractive and straightforward add-on to standard Si technology. #12
Technische Universiteit Delft
Silicon-Germanium Films Deposited by Low Frequency PE CVD: Effect of H2 and Ar Dilution
We have studied structure and electrical properties of Si{sub 1-Y}Ge{sub Y}:H films deposited by low frequency PE CVD over the entire composition range from Y=0 to Y=1. The deposition rate of the films and their structural and electrical properties were measured for various ratios of the germane/silane feed gases and with and without dilution by Ar and by H{sub 2}. Structure and composition was studied by Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS) and Fourier transform infrared (FTIR) spectroscopy. Surface morphology was characterized by atomic force microscopy (AFM). We found: (1) The deposition rate increased with Y maximizing at Y=1 without dilution. (2) The relative rate of Ge and Si incorporation is affected by dilution. (3) Hydrogen preferentially bonds to silicon. (4) Hydrogen content decreases for increasing Y. In addition, optical measurements showed that as Y goes for 0 to 1, the Fermi level moves from mid gap to the conduction band edge, i.e. the films become more n-type. No correlation was found between the pre-exponential and the activation energy of conductivity. The behavior of the conductivity {gamma}-factor suggests a local minimum in the density of states at E {approx} 0.33 eV for the films grown with or without H-dilution and E {approx} 0.25 eV for the films with Ar dilution.
Kosarev, A; Torres, A; Hernandez, Y; Ambrosio, R; Zuniga, C; Felter, T E; Asomoza, R R; Kudriavtsev, Y; Silva-Gonzalez, R; Gomez-Barojas, E; Ilinski, A; Abramov, A S
(Ti,Mg)N Thin Film Coatings Produced Via Physical Vapor Deposition
Magnesium (Mg) doped TiN was prepared via physical vapor deposition to ... Axial Compression of a Hollow Cylinder Filled with a Foam: A Porcupine Quill�...
Performance and analysis of amorphous silicon p-i-n solar cells made by chemical-vapor deposition from disilane
The photovoltaic performance of amorphous silicon p-i-n solar cells made by chemical-vapor deposition (CVD) from disilane is reported and analyzed. Intrinsic layers were deposited at rates from 0.2 to 50 A/s at temperatures from 380 to 460 /sup 0/C with and without boron doping. Device performance was insensitive to substantial differences in disilane purity. A cell efficiency of 4% was achieved. The primary limitation to higher efficiency was low fill factor (<50%) due to high series resistance (>18 ..cap omega.. cm/sup 2/). Analysis of the series resistance indicated a contact-related resistance of 4--12 ..cap omega.. cm/sup 2/ and a photoconductive resistance composed of intrinsic layer thickness-independent (10 ..cap omega.. cm/sup 2/) and thickness-dependent terms. Analysis of the voltage dependence of the current collection indicated a fill factor of 60% would be expected in the absence of series resistance. The maximum short-circuit current of 12.5 mA/cm/sup 2/ (normalized to 100 mW/cm/sup 2/) resulted with a boron-doped i layer deposited at 440 /sup 0/C at 3.3 A/s. Modeling of the collection efficiency indicated collection widths up to 0.33 ..mu..m for boron-doped and 0.24 ..mu..m for undoped p-i-n devices. In order to achieve high-efficiency cells using CVD from disilane, the limitations imposed by low photoconductivity, a high density of states, and restricted cell design imposed by the high deposition temperatures would have to be overcome.
Hegedus, S.S.; Rocheleau, R.E.; Buchanan, W.; Baron, B.N.
Laser-induced fluorescence measurements and kinetic analysis of Si atom formation in a rotating disk chemical vapor deposition reactor
An extensive set of laser-induced fluorescence (LIF) measurements of Si atoms during the chemical vapor deposition (CVD) of silicon from silane and disilane in a research rotating disk reactor are presented. The experimental results are compared in detail with predictions from a numerical model of CVD from silane and disilane that treats the fluid flow coupled to gas-phase and gas-surface chemistry. The comparisons showed that the unimolecular decomposition of SiH[sub 2] could not account for the observed gas-phase Si atom density profiles. The H[sub 3]SiSiH [leftrightarrow] Si + SiH[sub 4] and H[sub 3]SiSiH + SiH[sub 2] [leftrightarrow] Si + Si[sub 2]H[sub 6] reactions are proposed as the primary Si atom production routes. The model is in good agreement with the measured shapes of the Si atom profiles and the trends in Si atom density with susceptor temperature, pressure, and reactant gas mixture. 33 refs., 12 figs., 3 tabs.
Ho, P.; Coltrin, M.E.; Breiland, W.G. (Sandia National Lab., Albuquerque, NM (United States))
Radiation monitoring with CVD Diamonds and PIN Diodes at BaBar
The BaBar experiment at the Stanford Linear Accelerator Center has been using two polycrystalline chemical vapor deposition (pCVD) diamonds and 12 silicon PIN diodes for radiation monitoring and protection of the Silicon Vertex Tracker (SVT). We have used the pCVD diamonds for more than 3 years, and the PIN diodes for 7 years. We will describe the SVT and SVT radiation monitoring system as well as the operational difficulties and radiation damage effects on the PIN diodes and pCVD diamonds in a high-energy physics environment.
Bruinsma, M.; Burchat, P.; Curry, S.; Edwards, A.J.; Kagan, H.; Kass, R.; Kirkby, D.; Majewski, S.; Petersen, B.A.; /UC, Irvine /SLAC /Ohio State U.
Lithium phosphorous oxynitride films synthesized by a plasma-assisted directed vapor deposition approach
Lithium phosphorous oxynitride films synthesized by a plasma-assisted directed vapor deposition vapor deposition approach has been explored for the synthesis of lithium phosphorous oxynitride Lipon the ionic transport properties of these films. This enabled the synthesis of electrolyte films with lithium
Wadley, Haydn
Synthesis of high-quality monolayer and bilayer graphene on copper using chemical vapor deposition
/IG of the Raman spectra (red line in Fig. 6a) taken from the graphene grown on high purity Cu (99.999%) is above 3Synthesis of high-quality monolayer and bilayer graphene on copper using chemical vapor deposition determining the growth of high-quality monolayer and bilayer graphene on Cu using chemical vapor deposition
Plasma and Ion Assistance in Physical Vapor Deposition: AHistorical Perspective
Deposition of films using plasma or plasma-assist can betraced back surprisingly far, namely to the 18th century for arcs and tothe 19th century for sputtering. However, only since the 1960s thecoatings community considered other processes than evaporation for largescale commercial use. Ion Plating was perhaps the first importantprocess, introducing vapor ionization and substrate bias to generate abeam of ions arriving on the surface of the growing film. Ratherindependently, cathodic arc deposition was established as an energeticcondensation process, first in the former Soviet Union in the 1970s, andin the 1980s in the Western Hemisphere. About a dozen various ion-basedcoating technologies evolved in the last decades, all characterized byspecific plasma or ion generation processes. Gridded and gridless ionsources were taken from space propulsion and applied to thin filmdeposition. Modeling and simulation have helped to make plasma and ionseffects to be reasonably well understood. Yet--due to the complex, oftennon-linear and non-equilibrium nature of plasma and surfaceinteractions--there is still a place for the experience plasma"sourcerer."
Anders, Andre
Low temperature photochemical vapor deposition of alloy and mixed metal oxide films
Method and apparatus for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor vapor(s) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor vapor(s) is formed by vaporization of one or more precursor materials, where the vaporization temperature(s) is selected to control the ratio of concentration of metals present in the precursor vapor(s) and/or the total precursor vapor pressure.
Liu, David K. (San Pablo, CA)
Effect of gas feeding methods on optical properties of GaN grown by rapid thermal chemical vapor deposition reactor
Keywords: Ga vacancies, GaN growth, gas feeding method, optical property, rapid thermal chemical vapor deposition (RTCVD), yellow luminescence
Sun Jung Kim; Young Hun Seo; Kee Suk Nahm; Yun Bong Hahn; Hyun Wook Shim; Eun-Kyung Suh; Kee Young Lim; Hyung Jae Lee
Fabrication of commercial-scale fiber-reinforced hot-gas filters by chemical vapor deposition
Goal was to fabricate a filter for removing particulates from hot gases; principal applications would be in advanced utility processes such as pressurized fluidized bed combustion or coal gasification combined cycle systems. Filters were made in two steps: make a ceramic fiber preform and coat it with SiC by chemical vapor infiltration (CVD). The most promising construction was felt/filament wound. Light, tough ceramic composite filters can be made; reinforcement by continuous fibers is needed to avoid brittleness. Direct metal to filter contact does not damage the top which simplifies installation. However, much of the filter surface of felt/filament wound structures is closed over by the CVD coating, and the surface is rough and subject to delamination. Recommendations are given for improving the filters.
White, L.R. [Minnesota Mining and Mfg. Co., St. Paul, MN (United States). New Products Dept.
All-Hot-Wire Chemical Vapor Deposition a-Si:H Solar Cells
Efficient hydrogenated amorphous silicon (a-Si:H) nip solar cells have been fabricated with all doped and undoped a-Si:H layers deposited by hot-wire chemical vapor deposition (HWCVD). The total deposition time of all layers, except the top ITO-contact, is less than 4 minutes.
Iwaniczko, E.; Wang, Q.; Xu, Y.; Nelson, B. P.; Mahan, A. H.; Crandall, R. S.; Branz, H. M.
Photoconduction efficiencies and dynamics in GaN nanowires grown by chemical vapor deposition and molecular beam epitaxy: A comparison study
The normalized gains, which determines the intrinsic photoconduction (PC) efficiencies, have been defined and compared for the gallium nitride (GaN) nanowires (NWs) grown by chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). By excluding the contributions of experimental parameters and under the same light intensity, the CVD-grown GaN NWs exhibit the normalized gain which is near two orders of magnitude higher than that of the MBE-ones. The temperature-dependent time-resolved photocurrent measurement further indicates that the higher photoconduction efficiency in the CVD-GaN NWs is originated from the longer carrier lifetime induced by the higher barrier height ({phi}{sub B} = 160 {+-} 30 mV) of surface band bending. In addition, the experimentally estimated barrier height at 20 {+-} 2 mV for the MBE-GaN NWs, which is much lower than the theoretical value, is inferred to be resulted from the lower density of charged surface states on the non-polar side walls.
Chen, R. S. [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Tsai, H. Y. [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Huang, Y. S. [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Chen, Y. T. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Chen, L. C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Chen, K. H. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)
Application of Thermochemical Modeling to Chemical Vapor Deposition
Thermochemical modeling of a CVD process is relatively easy as compared to developing a full computational fluid dynamics description coupled with reaction kinetics for a geometrically complex system. As such, a thermochemical computational study should be performed before embarking on the development of any new CVD process or material. The results of this kind of analysis can provide important information about whether the phases of interest are thermochemically allowed to form from a proposed precursor system. It can also indicate whether secondary phases can form, and give some idea as to the maximum theoretical efficiency of the process. All of this information is predicated on reaching chemical equilibrium in a system, which is the fundamental assumption of thermochemical analysis. Yet, the presumption of chemical equilibrium is not realistic given the relatively short residence time of precursors in CVD reactors. However, reactions will proceed toward equilibrium to a sufficient extent that it is a reasonable assumption for gaining process insights. In addition, it is possible to constrain equilibrium calculations to provide a more realistic result, for example, by eliminating a phase from consideration when it is known that kinetic or steric conditions will prevent its formation even when it is thermochemically permitted.
Besmann, Theodore M [ORNL
Chemical vapor deposition of amorphous semiconductor films. Semiannual report, 1 May 1983-31 October 1984
This report presents an analysis of intrinsic and phosphorus-doped n-type amorphous silicon films deposited by LPCVD from disilane in a laminar flow tubular reactor. These films were analyzed using SIMs, ESR measurements, optical absorption, and conductivity in light and dark. CVD deposited i layers were used to make platinum Schottky barrier devices and hybrid cells utilizing glow discharge deposited layers in both the ITO/nip/Mo and ITO/pin/Mo configurations. The highest efficiency of hybrid cells with the ITO/ni(CVD)/p(GD)/Mo structure was approximately 1.5%. The highest efficiencies were obtained with thin i layers. The highest efficiency for the ITO/p(GD)/in(CVD)/Mo configuration was 4.0%. A chemical model was developed describing the gas phase reactions and film growth; the model quantitatively describes the effluent composition when the measured growth rate is input. Kinetic rate expressions and constants for growth from higher silanes are being determined for a wide range of reaction conditions.
Single- and few-layer graphene by ambient pressure chemical vapor deposition on nickel
An ambient pressure chemical vapor deposition (APCVD) process is used to fabricate graphene based films consisting of one to several graphene layers across their area. Polycrystalline Ni thin films are used and the graphene ...
Reina Ceeco, Alfonso
Optimal design of a high pressure organometallic chemical vapor deposition reactor
A team composed of material scientists, physicists, and applied mathematicians have used computer simulations as a fundamental design tool in developing a new prototype High Pressure Organometallic Chemical Vapor Deposition (HPOMCVD) reactor for use ...
K. J. Bachmann; H. T. Banks; C. H�pfner; G. M. Kepler; S. Lesure; S. D. Mccall; J. S. Scroggs
Raman scattering of polycrystalline 3C-SiC film deposited on AlN buffer layer by using CVD with HMDS
This paper presents the Raman scattering characteristics of poly (polycrystalline) 3C-SiC thin films deposited on AlN buffer layer by atmospheric pressure chemical vapor deposition (APCVD) using hexamethyldisilane (MHDS) and carrier gases (Ar+H"2). The ... Keywords: AlN, HMDS, Poly 3C-SiC, Raman scattering
Gwiy-Sang Chung; Kang-San Kim
Solar-induced chemical vapor deposition of diamond-type carbon films
An improved chemical vapor deposition method for depositing transparent continuous coatings of sp[sup 3]-bonded diamond-type carbon films, comprises: (a) providing a volatile hydrocarbon gas/H[sub 2] reactant mixture in a cold wall vacuum/chemical vapor deposition chamber containing a suitable substrate for said films, at pressure of about 1 to 50 Torr; and (b) directing a concentrated solar flux of from about 40 to about 60 watts/cm[sup 2] through said reactant mixture to produce substrate temperatures of about 750 C to about 950 C to activate deposition of the film on said substrate. 11 figs.
Pitts, J.R.; Tracy, C.E.; King, D.E.; Stanley, J.T.
An improved chemical vapor deposition method for depositing transparent continuous coatings of sp.sup.3 -bonded diamond-type carbon films, comprising: a) providing a volatile hydrocarbon gas/H.sub.2 reactant mixture in a cold wall vacuum/chemical vapor deposition chamber containing a suitable substrate for said films, at pressure of about 1 to 50 Torr; and b) directing a concentrated solar flux of from about 40 to about 60 watts/cm.sup.2 through said reactant mixture to produce substrate temperatures of about 750.degree. C. to about 950.degree. C. to activate deposition of the film on said substrate.
Pitts, J. Roland (Lakewood, CO); Tracy, C. Edwin (Golden, CO); King, David E. (Lakewood, CO); Stanley, James T. (Beaverton, OR)
Chemical vapor deposition growth. Quarterly report No. 2
The objective of the program is the development of CVD techniques for producing large areas of Si sheet on inexpensive substrate materials, with sheet properties suitable for fabricating solar cells meeting the technical goals of the Low Cost Silicon Solar Array Project (LCSSAP). The techniques developed are to be directed toward (1) minimum-cost processing, (2) production of sheet having properties adequate to result in cells with terrestrial array efficiency of 10 percent or more, and (3) eventual scale-up to large-quantity production. (WDM)
Ruth, R.P.; Manasevit, H.M.; Kenty, J.L.; Mondy, L.A.; Simpson, W.I.; Yang, J.J.
TEOS-based SiO{sub 2} chemical vapor deposition: Reaction kinetics and related surface chemistry
We have developed a comprehensive understanding of thermal TEOS (tetracthylorthosificate, Si(OCH{sub 2}CH{sub 3}){sub 4}) surface chemistry at CVD (chemical vapor deposition) temperatures and pressures. This was accomplished by examining how TEOS reaction rate are influenced by factors critical to the heterogeneous reaction. This includes determining the TEOS pressure dependence, testing if reaction by-products inhibit TEOS decomposition, identifying reaction sites on the surface, and establishing the reaction sites coverage dependencies. We evaluated the pressure dependencies and by-product inhibition with GCMS. The experiments in a cold-wall research reactor revealed that the TEOS surface reaction at 1000K (1) was first-order with respect to TEOS pressure (0.10 to 1.50Torr) and (2) was not inhibited by surface reaction by-products (ethylene, ethanol, and water). Reactivities of surface sites and their coverage dependencies were compared with FTIR. Our experiments demonstrated that two-membered siloxane ((Si-O){sub 2}) rings on the SiO{sub 2} surface were consumed almost instantaneously when exposed to TEOS. Our FTIR experiments also revealed that TEOS decomposition was zero-order with respect to coverages of hydroxyl groups and (by indirect evidence) three-membered siloxane ((Si-O){sub 3}) rings. This type of site-independent reactivity is consistent with TEOS reacting with hydroxyl groups and (Si-O){sub 3} rings via a common rate-determining step at 1000K. With respect to deposition uniformity, our results predict that deposition rates will be insensitive to the relative coverages of (Si-O){sub 3} rings and hydroxyls on SiO{sub 2} as well as the re-adsorbed by-products of the surface reaction. Therefore, it is likely that nonuniform SiO{sub 2} depositions from TEOS reactions are due to depletion of TEOS in the gas-phase and/or thermal gradients.
Bartram, M.E.; Moffat, H.K.
Formation of amorphous metal alloys by chemical vapor deposition
Amorphous alloys are deposited by a process of thermal dissociation of mixtures or organometallic compounds and metalloid hydrides, e.g., transition metal carbonyl such as nickel carbonyl, and diborane. Various sizes and shapes of deposits can be achieved, including near-net-shape free standing articles, multilayer deposits, and the like. Manipulation or absence of a magnetic field affects the nature and the structure of the deposit.
Mullendore, Arthur W. (Sandia Park, NM)
Demonstration of spatially programmable chemical vapor deposition: Model-based uniformity/nonuniformity control
Demonstration of spatially programmable chemical vapor deposition: Model-based uniformity of deposition experiments to develop a model relating precursor concentration to film thickness in each segment region. As a demonstration of spatial programmability, the system was reprogramed using this model
Rubloff, Gary W.
Chemical vapor deposition of W-Si-N and W-B-N
A method of depositing a ternary, refractory based thin film on a substrate by chemical vapor deposition employing precursor sources of tungsten comprising WF.sub.6, either silicon or boron, and nitrogen. The result is a W--Si--N or W--B--N thin film useful for diffusion barrier and micromachining applications.
Fleming, James G. (Albuquerque, NM); Roherty-Osmun, Elizabeth Lynn (Albuquerque, NM); Smith, Paul M. (Albuquerque, NM); Custer, Jonathan S. (Albuquerque, NM); Jones, Ronald V. (Albuquerque, NM); Nicolet, Marc-A. (Pasadena, CA); Madar, Roland (Eybens, FR); Bernard, Claude (Brie et Angonnes, FR)
Development of a polysilicon process based on chemical vapor deposition (Phase 1). First quarterly progress report, 6 October-31 December 1979
The goal of this program is to demonstrate that a dichlorosilane based reductive chemical vapor deposition (CVD) process is capable of producing, at low cost, high quality polycrystalline silicon. Physical form and purity of this material will be consistent with LSA material requirements for use in the manufacture of high efficiency solar cells. Chemical processes involved in achieving the objective are reviewed with emphasis placed on advantages of this process when compared with existing polycrystalline silicon production technology. Installation of a CVD reactor with associated analytical instrumentation is described. Preliminary reactor data has been favorable demonstrating the anticipated increased deposition rate and conversion efficiency when dichlorosilane decomposition is compared with trichlorosilane decomposition. No serious problems have been encountered which might limit dichlorosilane use as a reactor feed material. Design considerations for a process development unit (PDU) for dichlorosilane synthesis are reviewed. A design which effectively suppresses monochlorosilane during the redistribution of trichlorosilane was decided upon and its implementation is described. The PDU will be used to collect data on optimization of the redistribution process as well as to determine product quality. Based on experimental data collected during the first quarter along with already available data on the redistribution and hydrogenation processes, a preliminary mass balance is established.
McCormick, J. R.; Arvidson, A.; Plahutnik, F.; Sawyer, D.; Sharp, K.
Hot Wire Chemical Vapor Deposition with Carbide Filaments ...
Many of the current industry cells in production have come through NREL, ... One deposition technology utilized at NREL deals with hot wire chemical ...
The Effect of High Temperature Annealing on the Grain Characteristics of a Thin Chemical Vapor Deposition Silicon Carbide Layer.
The unique combination of thermo-mechanical and physiochemical properties of silicon carbide (SiC) provides interest and opportunity for its use in nuclear applications. One of the applications of SiC is as a very thin layer in the TRi-ISOtropic (TRISO) coated fuel particles for high temperature gas reactors (HTGRs). This SiC layer, produced by chemical vapor deposition (CVD), is designed to withstand the pressures of fission and transmutation product gases in a high temperature, radiation environment. Various researchers have demonstrated that macroscopic properties can be affected by changes in the distribution of grain boundary plane orientations and misorientations [1 - 3]. Additionally, various researchers have attributed the release behavior of Ag through the SiC layer as a grain boundary diffusion phenomenon [4 - 6]; further highlighting the importance of understanding the actual grain characteristics of the SiC layer. Both historic HTGR fission product release studies and recent experiments at Idaho National Laboratory (INL) [7] have shown that the release of Ag-110m is strongly temperature dependent. Although the maximum normal operating fuel temperature of a HTGR design is in the range of 1000-1250�C, the temperature may reach 1600�C under postulated accident conditions. The aim of this specific study is therefore to determine the magnitude of temperature dependence on SiC grain characteristics, expanding upon initial studies by Van Rooyen et al, [8; 9].
Isabella J van Rooyen; Philippus M van Rooyen; Mary Lou Dunzik-Gougar
Improved process for the preparation of fiber-reinforced ceramic composites by chemical vapor deposition
A specially designed apparatus provides a steep thermal gradient across the thickness of fibrous preform. A flow of gaseous ceramic matrix material is directed into the fibrous preform at the cold surface. The deposition of the matrix occurs progressively from the hot surface of the fibrous preform toward the cold surface. Such deposition prevents the surface of the fibrous preform from becoming plugged. As a result thereof, the flow of reactant matrix gases into the uninfiltrated (undeposited) portion of the fibrous preform occurs throughout the deposition process. The progressive and continuous deposition of ceramic matrix within the fibrous preform provides for a significant reduction in process time over known chemical vapor deposition processes.
Lackey, W.J. Jr.; Caputo, A.J.
Chemical vapor deposition of ZrC in small bore carbon-composite tubes
Process conditions are described for the chemical vapor deposition of ZrC from ZrCl/sub 4/--CH/sub 4/--HCl--H/sub 2/--Ar vapor over the temperature range 1320 to 1775 deg K. From an analysis of the process conditions (initial composition of coating gas, axial temperature profile along the tubes, total pressure, and length of deposition time), the subsequent ZrC coat thickness profiles and thermodynamic data, an equation expressing the variation of the axial rate of ZrC deposition is derived. This expression can be used for the estimation of process conditions required to yield a specified ZrC coat profile. Variations of the chlorine and oxygen contents, lattice pararmeter, microstructure of the ZrC deposit and thermal expansion coefficient as a function of deposition temperature are described. (11 figures, 3 tables) (auth)
Wallace, T.C.
Development of a polysilicon process based on chemical vapor deposition. Phase 1. Fourth quarterly progress report, 1 July-30 September 1980
The goal of this program is to demonstrate that a dichlorosilane-based reductive chemical vapor deposition (CVD) process is capable of producing, at low cost, high quality polycrystalline silicon for use in the manufacture of high efficiency solar cells. The feasibility of silicon generation from dichlorosilane (DCS) has been well established. The feasibility and optimization portions of the experimental reactor program have been completed, with a number of runs having been conducted over a broad range of conditions in an experimental CVD reactor. Activities relating to feed of commercially purchased DCS to an intermediate sized reactor and to construction of a Process Development Unit (PDU) to generate and feed DCS to one or more production scale reactors were suspended during the previous quarter because of the receipt of new safety-related information about DCS from Hazards Research Corp. Experimental data generated by Hazards Research Corp. indicate that DCS/air mixtures possess about four times the explosive severity potential as hydrogen/air mixtures, and that DCS/air mixtures are very readily ignited. As a consequence of this new information, designs and procedures for the intermediate reactor feed and PDU tasks were deemed inadequate and new designs incorporating new safety-related elements are being formulated. A preliminary economic evaluation of the Hemlock Semiconductor process has been completed. The analysis for a plant to generate 1000 metric tonne of silicon indicates a plant investment of $21.9 M, and a product selling price of $19.85/kg.
Sharp, K.; Arvidson, A.; Sawyer, D.
Effects of pressure, temperature, and hydrogen during graphene growth on SiC(0001) using propane-hydrogen chemical vapor deposition
Graphene growth from a propane flow in a hydrogen environment (propane-hydrogen chemical vapor deposition (CVD)) on SiC differentiates from other growth methods in that it offers the possibility to obtain various graphene structures on the Si-face depending on growth conditions. The different structures include the (6{radical}3 Multiplication-Sign 6{radical}3)-R30 Degree-Sign reconstruction of the graphene/SiC interface, which is commonly observed on the Si-face, but also the rotational disorder which is generally observed on the C-face. In this work, growth mechanisms leading to the formation of the different structures are studied and discussed. For that purpose, we have grown graphene on SiC(0001) (Si-face) using propane-hydrogen CVD at various pressure and temperature and studied these samples extensively by means of low energy electron diffraction and atomic force microscopy. Pressure and temperature conditions leading to the formation of the different structures are identified and plotted in a pressure-temperature diagram. This diagram, together with other characterizations (X-ray photoemission and scanning tunneling microscopy), is the basis of further discussions on the carbon supply mechanisms and on the kinetics effects. The entire work underlines the important role of hydrogen during growth and its effects on the final graphene structure.
Michon, A.; Vezian, S.; Roudon, E.; Lefebvre, D.; Portail, M. [CNRS-CRHEA, Rue Bernard Gregory, 06560 Valbonne (France)] [CNRS-CRHEA, Rue Bernard Gregory, 06560 Valbonne (France); Zielinski, M.; Chassagne, T. [NOVASiC, Savoie Technolac, Arche Bat 4, BP267, 73375 Le Bourget du Lac (France)] [NOVASiC, Savoie Technolac, Arche Bat 4, BP267, 73375 Le Bourget du Lac (France)
The Effect of Excess Carbon on the Crystallographic, Microstructural, and Mechanical Properties of CVD Silicon Carbide Fibers
Silicon carbide (SiC) fibers made by chemical vapor deposition (CVD) are of interest for organic, ceramic, and metal matrix composite materials due their high strength, high elastic modulus, and retention of mechanical properties at elevated processing and operating temperatures. The properties of SCS-6{trademark} silicon carbide fibers, which are made by a commercial process and consist largely of stoichiometric SiC, were compared with an experimental carbon-rich CVD SiC fiber, to which excess carbon was added during the CVD process. The concentration, homogeneity, and distribution of carbon were measured using energy dispersive x-ray spectroscopy (SEM/EDS). The effect of excess carbon on the tensile strength, elastic modulus, and the crystallographic and microstructural properties of CVD silicon carbide fibers was investigated using tensile testing, x-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
Marzik, J V; Croft, W J; Staples, R J; MoberlyChan, W J
Low-band-gap, amorphous-silicon-based alloys by photochemical vapor deposition: Final report, 1 October 1985--30 November 1986
Thin films of hydrogenated amorphous silicon-germanium alloys were deposited by mercury-sensitized photochemical vapor deposition using a novel photo-CVD reactor. Thin films of a-Si/sub 1-x/Ge/sub x/:H with 0 less than or equal to x less than or equal to 1 and 1.0 less than E/sub g/ less than 1.8 eV were deposited from mixtures of silane and disilane with germane and inert gas diluents at substrate temperatures from 160/degree/ to 200/degree/C. Alloy films were characterized by measurements of photo- and dark conductivity, electron mobility-lifetime product, sub-band-gap absorption, and density of states. Dilution with hydrogen increased the photoconductivity to 10/sup /minus/5/ Scm and mobility-lifetime product to 6 /times/ 10/sup /minus/8/ cm/sup 2/V for alloys having a band gap of 1.4 eV.
Baron, B.N.; Hegedus, S.S.; Jackson, S.C.
Aerosol chemical vapor deposition of metal oxide films
A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said substrate, and as having a crystalline orientation defined as predominantly C-axis oriented by x-ray diffraction is disclosed.
Ott, K.C.; Kodas, T.T.
Continuous growth of single-wall carbon nanotubes using chemical vapor deposition
The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.
Grigorian, Leonid (Raymond, OH); Hornyak, Louis (Evergreen, CO); Dillon, Anne C (Boulder, CO); Heben, Michael J (Denver, CO)
Metal organic chemical vapor deposition of 111-v compounds on silicon
Expitaxial composite comprising thin films of a Group III-V compound semiconductor such as gallium arsenide (GaAs) or gallium aluminum arsenide (GaAlAs) on single crystal silicon substrates are disclosed. Also disclosed is a process for manufacturing, by chemical deposition from the vapor phase, epitaxial composites as above described, and to semiconductor devices based on such epitaxial composites. The composites have particular utility for use in making light sensitive solid state solar cells.
Vernon, Stanley M. (Wellesley, MA)
Monolayer Graphene Growth on Ni(111) by Low Temperature Chemical Vapor Deposition
In contrast to the commonly employed high temperature chemical vapor deposition growth that leads to multilayer graphene formation by carbon segregation from the bulk, we demonstrate that below 600 C graphene can be grown in a self-limiting monolayer growth process. Optimum growth is achieved at {approx}550 C. Above this temperature, carbon diffusion into the bulk is limiting the surface growth rate, while at temperatures below {approx}500 C a competing surface carbide phase impedes graphene formation.
Batzill, M.; Sutter, P.; Addou, R.; Dahal, A.
Epitaxial Thin Film Silicon Solar Cells Fabricated by Hot Wire Chemical Vapor Deposition Below 750 ..deg..C: Preprint
We report on fabricating film c-Si solar cells on Si wafer templates by hot-wire chemical vapor deposition. These devices, grown at glass-compatible temperatures 500 mV and efficiencies > 5%.
Alberi, K.; Martin, I. T.; Shub, M.; Teplin, C. W.; Iwaniczko, E.; Xu, Y.; duda, A.; Stradin, P.; Johnston, S. W.; Romero, M. J.; Branz, H. M.; Young, D. L.
innovative designs using graphene in fields like electronicsof Entire CVD- Grown Graphene Sheets", Small 7(18): 2599-dimensional few layer graphene and carbon nanotube foam
Development of hybrid organic-inorganic light emitting diodes using conducting polymers deposited by oxidative chemical vapor deposition process
Difficulties with traditional methods of synthesis and film formation for conducting polymers, many of which are insoluble, motivate the development of CVD methods. Indeed, conjugated polymers with rigid linear backbones ...
Chelawat, Hitesh
Characteristics of Gd2-xLaxO3 high-k films by metal-organic chemical vapor deposition
Gd"2"-"xLa"xO"3 high-k films were deposited on (100) Si substrates by low-pressure metal-organic chemical vapor deposition (MOCVD). The metal-organic precursors we used were Gd and La @b-diketonates. The structure, band gap, composition and electrical ... Keywords: Gd2-xLaxO3, High- k, MOCVD
Liu-Ying Huang; Ai-Dong Li; Ying-Ying Fu; Wen-Qi Zhang; Xiao-Jie Liu; Di Wu
A comparison of diamond growth rate using in-liquid and conventional plasma chemical vapor deposition methods
In order to make high-speed deposition of diamond effective, diamond growth rates for gas-phase microwave plasma chemical vapor deposition and in-liquid microwave plasma chemical vapor deposition are compared. A mixed gas of methane and hydrogen is used as the source gas for the gas-phase deposition, and a methanol solution of ethanol is used as the source liquid for the in-liquid deposition. The experimental system pressure is in the range of 60-150 kPa. While the growth rate of diamond increases as the pressure increases, the amount of input microwave energy per unit volume of diamond is 1 kW h/mm{sup 3} regardless of the method used. Since the in-liquid deposition method provides a superior cooling effect through the evaporation of the liquid itself, a higher electric input power can be applied to the electrodes under higher pressure environments. The growth rate of in-liquid microwave plasma chemical vapor deposition process is found to be greater than conventional gas-phase microwave plasma chemical vapor deposition process under the same pressure conditions.
Takahashi, Yoshiyuki; Toyota, Hiromichi; Nomura, Shinfuku; Mukasa, Shinobu [Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Inoue, Toru [Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)
Method of making AlInSb by metal-organic chemical vapor deposition
A method for producing aluminum-indium-antimony materials by metal-organic chemical vapor deposition (MOCVD). This invention provides a method of producing Al.sub.X In.sub.1-x Sb crystalline materials by MOCVD wherein an Al source material, an In source material and an Sb source material are supplied as a gas to a heated substrate in a chamber, said Al source material, In source material, and Sb source material decomposing at least partially below 525.degree. C. to produce Al.sub.x In.sub.1-x Sb crystalline materials wherein x is greater than 0.002 and less than one.
Biefeld, Robert M. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM); Baucom, Kevin C. (Albuquerque, NM)
Chemical vapor deposition techniques and related methods for manufacturing microminiature thermionic converters
Methods of manufacturing microminiature thermionic converters (MTCs) having high energy-conversion efficiencies and variable operating temperatures using MEMS manufacturing techniques including chemical vapor deposition. The MTCs made using the methods of the invention incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. The MTCs also exhibit maximum efficiencies of just under 30%, and thousands of the devices can be fabricated at modest costs.
King, Donald B. (Albuquerque, NM); Sadwick, Laurence P. (Salt Lake City, UT); Wernsman, Bernard R. (Clairton, PA)
Chemical Vapor Deposition of Fluoroalkylsilane Monolayer Films for Adhesion Control in Microelectromechanical Systems
We have developed a new process for applying a hydrophobic, low adhesion energy coating to microelectromechanical (MEMS) devices. Monolayer films are synthesized from tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) and water vapor in a low-pressure chemical vapor deposition process at room temperature. Film thickness is self-limiting by virtue of the inability of precursors to stick to the fluorocarbon surface of the film once it has formed. We have measured film densities of {approx}3 molecules nm{sup 2} and film thickness of {approx}1 nm. Films are hydrophobic, with a water contact angle >110{sup o}. We have also incorporated an in-situ downstream microwave plasma cleaning process, which provides a clean, reproducible oxide surface prior to film deposition. Adhesion tests on coated and uncoated MEMS test structures demonstrate superior performance of the FOTS coatings. Cleaned, uncoated cantilever beam structures exhibit high adhesion energies in a high humidity environment. An adhesion energy of 100 mJ m{sup -2} is observed after exposure to >90% relative humidity. Fluoroalkylsilane coated beams exhibit negligible adhesion at low humidity and {<=} 20 {micro}J m{sup -2} adhesion energy at >90% relative humidity. No obvious film degradation was observed for films exposed to >90% relative humidity at room temperature for >24 hr.
Electron beam physical vapor deposition of thin ruby films for remote temperature sensing
Thermographic phosphors (TGPs) possessing temperature-dependent photoluminescence properties have a wide range of uses in thermometry due to their remote access and large temperature sensitivity range. However, in most cases, phosphors are synthesized in powder form, which prevents their use in high resolution micro and nanoscale thermal microscopy. In the present study, we investigate the use of electron beam physical vapor deposition to fabricate thin films of chromium-doped aluminum oxide (Cr-Al{sub 2}O{sub 3}, ruby) thermographic phosphors. Although as-deposited films were amorphous and exhibited weak photoluminescence, the films regained the stoichiometry and {alpha}-Al{sub 2}O{sub 3} crystal structure of the combustion synthesized source powder after thermal annealing. As a consequence, the annealed films exhibit both strong photoluminescence and a temperature-dependent lifetime that decreases from 2.9 ms at 298 K to 2.1 ms at 370 K. Ruby films were also deposited on multiple substrates. To ensure a continuous film with smooth surface morphology and strong photoluminescence, we use a sapphire substrate, which is thermal expansion coefficient and lattice matched to the film. These thin ruby films can potentially be used as remote temperature sensors for probing the local temperatures of micro and nanoscale structures.
Li Wei; Coppens, Zachary J.; Greg Walker, D.; Valentine, Jason G. [Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37212 (United States)
Plasma Enhanced Chemical Vapor Deposition on Living Substrates: Development, Characterization, and Biological Applications
This dissertation proposed the idea of �plasma-enhanced chemical vapor deposition on living substrates (PECVD on living substrates)� to bridge the gap between the thin film deposition technology and the biological and living substrates. This study focuses on the establishment of the knowledge and techniques necessary to perform �PECVD on living substrates� and contains three main aspects: development, characterization, and biological applications. First, a PECVD tool which can operate in ambient air and at low temperature was developed using a helium dielectric barrier discharge jet (DBD jet). It was demonstrated that various materials, such as polymeric, metallic, and composite films, can be readily synthesized through this technique. Second, the PMMA and copper films deposited using DBD jets were characterized. High-rate (22 nm/s), low-temperature (39 �C) PMMA deposition was achieved and the film surface morphology can be tailored by altering the discharge power. Conductive copper films with an electrical resistivity lower than 1�10-7 ohm-m were obtained through hydrogen reduction. Both PMMA and copper films can be grown on temperature-sensitive substrates, such as plastics, pork skin, and even fingernail. The electrical, optical, and imaging characterization of the DBD jets was also conducted and several new findings were reported. Multiple short-duration current pulses instead of only one broad pulse per half voltage cycle were observed when a dielectric substrate was employed. Each short-duration current pulse is induced by a leading ionization wave followed by the formation of a plasma channel. Precursor addition further changed the temporal sequence of the pulses. An increase in the power led to a mode change from a diffuse DBD jet to a concentrated one. This mode change showed significant dependence on the precursor type, tube size, and electrode configuration. These findings regarding the discharge characteristics can thus facilitate the development of DBD-jet operation strategies to improve the deposition efficacy. Finally, this technique was used to grow PMMA films onto agar to demonstrate one of its potential biological applications: sterile bandage deposition. The DBD jet with the film depositing ability enabled the surface to be not only efficiently sanitized but also protected by a coating from being reached by bacteria.
Tsai, Tsung-Chan 1982-
Ion-assisted doping of 2-6 compounds during physical vapor deposition
This report describes a research program to (1) investigate ion-assisted doping during chemical vapor deposition of CdTe and (2) determine the influence of co-depositing ionized dopant atoms in the growth and structural and photoelectronic properties of the deposited films. In p-CdTe homo-epitaxial films, we controlled doping up to about 6 {times} 10{sup 16} cm{sup {minus}3} and 2 {times} 10{sup 17} cm{sub {minus}3} or ion-assisted depositions with As and P ions, respectively. At a growth rate of approximately 0.1 {mu}m/min, a substrate temperature of 400{degree}C, and ion energy of 60 eV, a maximum doping density was found near an ion current of 0.6{mu}A/cm{sup 2}. Related studies included elucidating the role of low-energy ion damage in the ion-assisted doping process, and investigating the decrease in carrier density near the surface of p-CdTe upon heating in vacuum, H{sub 2}, or Ar. We demonstrate the ability to make carrier density profiles and to grade junctions, and we present preliminary results from polycrystalline p-CdTe films grown on graphite and alumina substrates. We also present solar cells prepared using the p-CdTe as the collector area and n-CdS as the window layer, and we examine their photovoltaic parameters for different carrier densities and configurations in p-CdTe. 91 refs., 44 figs., 5 tabs.
Bube, R H [Stanford Univ., CA (USA). Dept. of Materials Science and Engineering
We report on fabricating film c-Si solar cells on Si wafer templates by hot-wire chemical vapor deposition. These devices, grown at glass-compatible temperatures < 750..deg..C, demonstrate open-circuit voltages > 500 mV and efficiencies > 5%.
Growth of homo-epitaxial silicon at low temperatures using hot wire chemical vapor deposition
The authors report on the first known growth of high-quality epitaxial Si via the hot wire chemical vapor deposition (HWCVD) method. This method yields device-quality epitaxial Si at the comparatively low temperatures of 195 to 450 C, and relatively high growth rates of 3 to 20 {angstrom}/sec. Layers up to 4,500-{angstrom} thick have been grown. These epitaxial layers have been characterized by transmission electron microscopy (TEM), indicating large regions of nearly perfect atomic registration. Electron channeling patterns (ECPs) generated on a scanning electron microscope (SEM) have been used to characterize as well as optimize the growth process. Electron beam induced current (EBIC) characterization has also been performed, indicating defect densities as low as 5 x 104/cm{sup 2}. Secondary ion beam mass spectrometry (SIMS) data shows that these layers have reasonable impurity levels within the constraints of the current deposition system. Both n and p-type layers were grown, and p/n diodes have been fabricated.
Thiesen, J.; Jones, K.M.; Matson, R.; Reedy, R.; Crandall, R.; Iwaniczko, E.; Mahan, H.
Verification of the O-Si-N complex in plasma-enhanced chemical vapor deposition silicon oxynitride films
Silicon oxynitride films were deposited using a plasma-enhanced chemical vapor deposition process. The bond configurations of the constituent atoms in the deposited film were analyzed using x-ray photoelectron spectroscopy. Analysis of the Si 2p spectra showed the presence of nonstoichiometric silicon oxide and silicon oxynitride. Analysis of the binding energy shifts induced by Si-O and Si-N bond formation indicated an O-Si-N complex was present in the film matrix. Component balance analysis indicated that second-nearest-neighbor bond interactions were not the cause of these energy shifts and supported the presence of an O-Si-N complex.
Naskar, Sudipto; Wolter, Scott D.; Bower, Christopher A.; Stoner, Brian R.; Glass, Jeffrey T. [Center for Materials and Electronics Technologies, RTI-International, Research Triangle Park, North Carolina 27709 and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States); Center for Materials and Electronics Technologies, RTI-International, Research Triangle Park, North Carolina 27709 (United States); Center for Materials and Electronics Technologies, RTI-International, Research Triangle Park, North Carolina 27709 and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States)
Chemical Vapor Deposition-Derived Graphene with Electrical Performance of Exfoliated Graphene
-effect mobility. These results confirm the possibility of achieving high-performance graphene devices based electrical performance comparable to that of high-quality exfoliated graphene. We grow single-layer graphene by more conventional CVD methods,1-3 which yield continuous films of polycrystal- line graphene with grain
Kim, Philip
Low temperature metal-organic chemical vapor deposition growth processes for high-efficiency solar cells
This report describes the results of a program to develop a more complete understanding of the physical and chemical processes involved in low-temperature growth of III-V compounds by metal-organic chemical vapor deposition (MOCVD) and to develop a low-temperature process that is suitable for the growth of high-efficiency solar cells. The program was structured to develop a better understanding of the chemical reactions involved in MOCVD growth, to develop a model of the processes occurring in the gas phase, to understand the physical kinetics and reactions operative on the surface of the growing crystal, and to develop an understanding of the means by which these processes may be altered to reduce the temperature of growth and the utilization of toxic hydrides. The basic approach was to develop the required information about the chemical and physical kinetics operative in the gas phase and on the surface by the direct physical measurement of the processes whenever possible. The program included five tasks: (1) MOCVD growth process characterization, (2) photoenhanced MOCVD studies, (3) materials characterization, (4) device fabrication and characterization, and (5) photovoltaic training. Most of the goals of the program were met and significant progress was made in defining an approach that would allow both high throughput and high uniformity growth of compound semiconductors at low temperatures. The technical activity was focused on determining the rates of thermal decomposition of trimethyl gallium, exploring alternate arsenic sources for use MOCVD, and empirical studies of atomic layer epitaxy as an approach.
Dapkus, P.D. (University of Southern California, Los Angeles, CA (United States))
Gas-phase reaction study of disilane pyrolysis: Applications to low pressure chemical vapor deposition
The gas-phase thermal reactions during disilane decomposition at low pressure chemical vapor deposition conditions were studied from 300 to 1,000 K using resonance enhanced multiphoton ionization (REMPI) and multiphoton ionization (MPI). REMPI of gas-phase Si, mass 28, was detected from 640 to 840 K and 1 to 10 Torr, with a maximum signal intensity between 700 to 720 K. During disilane decomposition, no SiH (427.8 nm), SiH[sub 2] (494-515 nm), or SiH[sub 3] (419.0 nm) was detected. MPI of higher silanes, silenes, and silylenes were detected through mass fragments 2, 32, and 60; these species reached a maximum signal intensity 20 degrees prior to the mass-28 maximum. Modeling studies that included a detailed low pressure gas-phase kinetic scheme predict relative gas-phase partial pressures generated during disilane pyrolysis. The model predicted experimental trends in the Si partial pressure and the higher silane, silene, and silylene partial pressures.
Johannes, J.E.; Ekerdt, J.G. (Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering)
Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders
This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.
Asit Biswas Andrew J. Sherman
On-line coating of glass with tin oxide by atmospheric pressure chemical vapor deposition.
Atmospheric pressure chemical vapor deposition (APCVD) of tin oxide is a very important manufacturing technique used in the production of low-emissivity glass. It is also the primary method used to provide wear-resistant coatings on glass containers. The complexity of these systems, which involve chemical reactions in both the gas phase and on the deposition surface, as well as complex fluid dynamics, makes process optimization and design of new coating reactors a very difficult task. In 2001 the U.S. Dept. of Energy Industrial Technologies Program Glass Industry of the Future Team funded a project to address the need for more accurate data concerning the tin oxide APCVD process. This report presents a case study of on-line APCVD using organometallic precursors, which are the primary reactants used in industrial coating processes. Research staff at Sandia National Laboratories in Livermore, CA, and the PPG Industries Glass Technology Center in Pittsburgh, PA collaborated to produce this work. In this report, we describe a detailed investigation of the factors controlling the growth of tin oxide films. The report begins with a discussion of the basic elements of the deposition chemistry, including gas-phase thermochemistry of tin species and mechanisms of chemical reactions involved in the decomposition of tin precursors. These results provide the basis for experimental investigations in which tin oxide growth rates were measured as a function of all major process variables. The experiments focused on growth from monobutyltintrichloride (MBTC) since this is one of the two primary precursors used industrially. There are almost no reliable growth-rate data available for this precursor. Robust models describing the growth rate as a function of these variables are derived from modeling of these data. Finally, the results are used to conduct computational fluid dynamic simulations of both pilot- and full-scale coating reactors. As a result, general conclusions are reached concerning the factors affecting the growth rate in on-line APCVD reactors. In addition, a substantial body of data was generated that can be used to model many different industrial tin oxide coating processes. These data include the most extensive compilation of thermochemistry for gas-phase tin-containing species as well as kinetic expressions describing tin oxide growth rates over a wide range of temperatures, pressures, and reactant concentrations.
Allendorf, Mark D.; Sopko, J.F. (PPF Industries, Pittsburgh, PA); Houf, William G.; Chae, Yong Kee; McDaniel, Anthony H.; Li, M. (PPF Industries, Pittsburgh, PA); McCamy, J.W. (PPF Industries, Pittsburgh, PA)
Silicon nucleation and film evolution on silicon dioxide using disilane: Rapid thermal chemical vapor deposition of very smooth silicon at high deposition rates
An investigation of Si{sub 2}H{sub 6} and H{sub 2} for rapid thermal chemical vapor deposition (RTCVD) of silicon on SiO{sub 2} has been performed at temperatures ranging from 590 to 900 C and pressures ranging from 0.1 to 1.5 Torr. Deposition at 590 C yields amorphous silicon films with the corresponding ultrasmooth surface with a deposition rate of 68 nm/min. Cross-sectional transmission electron microscopy of a sample deposited at 625 C and 1 Torr reveals a bilayer structure which is amorphous at the growth surface and crystallized at the oxide interface. Higher temperatures yield polycrystalline films where the surface roughness depends strongly on both deposition pressure and temperature. Silane-based amorphous silicon deposition in conventional systems yields the expected ultrasmooth surfaces, but at greatly reduced deposition rates unsuitable for single-wafer processing. However, disilane, over the process window considered here, yields growth rates high enough to be appropriate for single-wafer manufacturing, thus providing a viable means for deposition of very smooth silicon films on SiO{sub 2} in a single-wafer environment.
Violette, K.E.; Oeztuerk, M.C.; Christensen, K.N.; Maher, D.M. [North Carolina State Univ., Raleigh, NC (United States)
Properties of In-Doped ZnO Films Grown by Metalorganic Chemical Vapor Deposition on GaN(0001) Templates
TCO is amor- phous indium tin oxide (ITO), most commonlythe properties of indium-doped zinc oxide layers grown byoxide, doping, n-type, MOCVD, metalorganic chemical vapor deposition, ZnO: In, indium
Ben-Yaacov, Tammy; Ive, Tommy; Walle, Chris G.; Mishra, Umesh K.; Speck, James S.; Denbaars, Steven P.
On the Potential Change in Surface Water Vapor Deposition over the Continental United States due to Increases in Atmospheric Greenhouse Gases
Characteristics of surface water vapor deposition (WVD) over the continental United States under the present climate and a future climate scenario reflecting the mid-twenty-first-century increased greenhouse gas concentrations were evaluated by ...
Zaitao Pan; Moti Segal; Charles Graves
Organic-vapor-liquid-solid deposition with an impinging gas jet Daniel W. Shaw, Kevin Bufkin, Alexandr A. Baronov, Brad L. Johnson, and David L. Patrick
Organic-vapor-liquid-solid deposition with an impinging gas jet Daniel W. Shaw, Kevin Bufkin gas jet to a substrate coated by a thin liquid solvent layer. Films of the organic semiconductor, and the results compared to experiment. The combination of gas jet delivery with an organic-vapor-liquid
Patrick, David L.
CVD Equipment Corp | Open Energy Information
Open Energy Info (EERE)
CVD Equipment Corp CVD Equipment Corp Jump to: navigation, search Name CVD Equipment Corp Place Ronkonkoma, New York Zip 11779 Sector Solar Product New York-based maker of chemical vapour deposition process equipment. This equipment is used in the manufacture of solar and semiconductor fabrication. Coordinates 40.81122°, -73.098744° 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":40.81122,"lon":-73.098744,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Plasma enhanced chemical vapor deposition (PECVD) method of forming vanadium oxide films and vanadium oxide thin-films prepared thereby
A method is disclosed of forming a vanadium oxide film on a substrate utilizing plasma enhanced chemical vapor deposition. The method includes positioning a substrate within a plasma reaction chamber and then forming a precursor gas comprised of a vanadium-containing chloride gas in an inert carrier gas. This precursor gas is then mixed with selected amounts of hydrogen and oxygen and directed into the reaction chamber. The amounts of precursor gas, oxygen and hydrogen are selected to optimize the final properties of the vanadium oxide film An rf plasma is generated within the reaction chamber to chemically react the precursor gas with the hydrogen and the oxygen to cause deposition of a vanadium oxide film on the substrate while the chamber deposition pressure is maintained at about one torr or less. Finally, the byproduct gases are removed from the plasma reaction chamber.
Zhang, Ji-Guang (Golden, CO); Tracy, C. Edwin (Golden, CO); Benson, David K. (Golden, CO); Turner, John A. (Littleton, CO); Liu, Ping (Lakewood, CO)
Nitrogen actinometry for measurement of nitrogen radical spatial distribution in large-area plasma-enhanced chemical vapor deposition
Density distributions of radicals in the large-area silicon nitride (Si{sub 3}N{sub 4}) plasma-enhanced chemical vapor deposition (PECVD) process were measured using a spatially resolvable optical emission spectrometer (SROES). To determine the qualitative distribution of a target radical, the authors used optical actinometry with nitrogen (N{sub 2}) gas as an actinometer. To compare the SROES data and process results, the thickness of the deposited Si{sub 3}N{sub 4} thin films using an ellipsometer was measured. By introducing nitrogen-based optical actinometry, the authors obtained very good agreement between the experimental results of the distributions of atomic nitrogen radical and the deposited thicknesses of Si{sub 3}N{sub 4} thin films. Based on these experimental results, the uniformity of the process plasma in the PECVD process at different applied radio frequency powers was analyzed.
Oh, Changhoon; Kang, Minwook; Hahn, Jae W. [Nano Photonics Laboratory, School of Mechanical Engineering, Yonsei University, 50 Yonesi-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Nam, Seungsuk [Based Technology of Equipment Team, LG Display, Paju-City, Gyeonggi-do 413-811 (Korea, Republic of)
Raman spectroscopic study of carbon nanotubes prepared using Fe/ZnO-palm olein-chemical vapour deposition
Multiwalled carbon nanotubes (MWCNTs) were synthesized using Fe/ZnO catalyst by a dual-furnace thermal chemical vapor deposition (CVD) method at 800-1000�C using nitrogen gas with a constant flow rate of 150 sccm/min as a gas carrier. Palm olein ...
Syazwan Afif Mohd Zobir; Suriani Abu Bakar; Saifollah Abdullah; Zulkarnain Zainal; Siti Halimah Sarijo; Mohamad Rusop
Real-time optical diagnostics of graphene growth induced by pulsed chemical vapor deposition
The kinetics and mechanisms of graphene growth on Ni films at 720 -880 C have been measured using fast pulses of acetylene and real-time optical diagnostics. In situ UV-Raman spectroscopy was used to unambiguously detect isothermal graphene growth at high temperatures, measure the growth kinetics with ~ 1s temporal resolution, and estimate the fractional precipitation upon cooldown for the first time. Optical reflectivity and videography provided much faster temporal resolution. Both the growth kinetics and the fractional isothermal precipitation were found to be governed by the C2H2 partial pressure in the CVD pulse for a given film thickness and temperature, with up to ~ 94% of graphene growth occurring isothermally within 1 second at 800 C at high partial pressures. At lower partial pressures, isothermal graphene growth is shown to continue 10 seconds after the gas pulse. These flux-dependent growth kinetics are described in the context of a dissolution/precipitation model, where carbon rapidly dissolves into the Ni film and later precipitates driven by gradients in the chemical potential. The combination of pulsed-CVD and real-time optical diagnostics opens new opportunities to understand and control the fast, sub-second growth of graphene on various substrates at high temperatures.
Puretzky, Alexander A [ORNL; Geohegan, David B [ORNL; Pannala, Sreekanth [ORNL; Rouleau, Christopher M [ORNL; Regmi, Murari [Oak Ridge National Laboratory (ORNL); Thonnard, Norbert [ORNL; Eres, Gyula [ORNL
Towards improved spinnability of chemical vapor deposition generated multi-walled carbon nanotubes
and Dresselhaus G. 1997 From Carbon Fibers to Nanotubes inV VGCF Vapor Grown Carbon Fiber X XRD X-ray Diffraction ixgraphite whiskers, carbon fibers, and carbon nanotubes, each
McKee, Gregg Sturdivant Burke
Use of Optical Microscopy to Examine Crystallite Nucleation and Growth in Thermally Annealed Plasma Enhanced Chemical Vapor Deposition and Hot Wire Chemical Vapor Deposition a-Si:H Films
We report a simple method to investigate crystallite nucleation and growth in stepwise, thermally annealed plasma enhanced chemical vapor deposition and hot wire chemical vapor deposition a-Si:H films. By confining film thicknesses to the range 500-4000 {angstrom}, optical microscopy in the reflection mode can be used to readily detect crystallites in the thermally annealed a-Si:H lattice. Measurements of the crystallite density versus annealing time for identically prepared films of different thickness show that the crystallite nucleation rate is smaller for thinner films, suggesting that crystallite nucleation is homogeneous, in agreement with previous results. A comparison of film nucleation rates with those obtained by other methods on identically prepared films shows excellent agreement, thus establishing the validity of the current technique. The potential effect of impurity (oxygen) incorporation during the stepwise annealing in air is shown not to affect crystallite nucleation and growth, in that SIMS oxygen profiles for stepwise versus continuous annealing show not only similar impurity profiles but also similar bulk impurity densities.
Mahan, A. H.; Dabney, M. S.; Reedy, Jr R. C.; Molina, D.; Ginley, D. S.
CVD synthesis of hierarchical 3D MWCNT/carbon-fiber nanostructures
Multiwalled carbon nanotubes (MWCNTs) were synthesized by CVD on industrially manufactured highly crystalline vapor-grown carbon fibers (VGCFs). Two catalyst metals (Ni and Fe) and carbon precursor gases (C2H2 and CO) were studied. ...
Toma Susi; Albert G. Nasibulin; Hua Jiang; Esko I. Kauppinen
Maskless deposition technique for the physical vapor deposition of thin film and multilayer coatings with subnanometer precision and accuracy
The invention is a method for the production of axially symmetric, graded and ungraded thickness thin film and multilayer coatings that avoids the use of apertures or masks to tailor the deposition profile. A motional averaging scheme permits the deposition of uniform thickness coatings independent of the substrate radius. Coating uniformity results from an exact cancellation of substrate radius dependent terms, which occurs when the substrate moves at constant velocity. If the substrate is allowed to accelerate over the source, arbitrary coating profiles can be generated through appropriate selection and control of the substrate center of mass equation of motion. The radial symmetry of the coating profile is an artifact produced by orbiting the substrate about its center of mass; other distributions are obtained by selecting another rotation axis. Consequently there is a direct mapping between the coating thickness and substrate equation of motion which can be used to tailor the coating profile without the use of masks and apertures.
Vernon, Stephen P. (Pleasanton, CA); Ceglio, Natale M. (Livermore, CA)
Vapor-Phase Metalation by Atomic Layer Deposition in a Metal-Organic Framework
encompass deposition onto micro- and nanopowders14 and coating of nanoparticle films15 as well as aerogel coating of porous materials that exhibit ultrahigh-aspect ratios.12,13 To date, some striking examples
High Growth Rate of Epitaxial Silicon-Carbon Alloys by High-Order Silane Precursor and Chemical Vapor Deposition
rates typically achieved by disilane and silane, respectively, at 575o C. The rate at present is limited precursor HOS than disilane in CVD, even at lower temperatures. Our current growth rates of Si1-yCy alloys
Equilibrium predictions of the role of organosilicon compounds in the chemical vapor deposition of silicon carbide
Equilibrium calculations are reported for a range of conditions used to deposit silicon carbide (SiC) from Si-C-H mixtures such as those using SiH{sub 4}, C{sub 2}H{sub 4}, and H{sub 2} as reactants. Included are 37 molecules containing both silicon and carbon, allowing as assessment to be made of the importance of organosilicon species to the deposition process. The results indicate that Si{sub 2}C and SiCH{sub 2} may contribute to epitaxial SiC deposition and that formation of these and other organosilicon species is favored by low H{sub 2} concentrations. In addition, simulations of gas-phase equilibria expected under low-pressure, low-temperature conditions show that some organosilicon radicals that are kinetically favored are also thermodynamically favored. These include SiC{sub 2}, SiCCH, and HSiCCH, which could results from the reactor of SiH{sub 2} with unsaturated reactants such as C{sub 2}H{sub 2}. The results suggest that combining an inert carrier gas with an excess of a surface-reactive hydrocarbon such as C{sub 2}H{sub 2} could increase deposition rates without forming silicon-rich deposits. 25 refs.
Allendorf, M.D.
Vapor-Phase-Deposited Organosilane Coatings as "Hardening" Agents for High-Peak-Power Laser Optics
Multilayer-dielectric (MLD) diffraction gratings are used in high-power laser systems to compress laser-energy pulses. The peak power deliverable on target for these short-pulse petawatt class systems is limited by the laser-damage resistance of the optical components in the system, especially the MLD gratings. Recent experiments in our laboratory have shown that vapor treatment of MLD gratings at room temperature with organosilanes such as hexamethyldisilazane (HMDS) produces an increase in their damage threshold as compared to uncoated MLD grating control samples.
Marshall, K.L.; Culakova, Z.; Ashe, B.; Giacofei, C.; Rigatti, A.L.; Kessler, T.J.; Schmid, A.W.; Oliver, J.B.; Kozlov, A.
High temperature step-flow growth of gallium phosphide by molecular beam epitaxy and metalorganic chemical vapor deposition
Post-growth surface morphologies of high-temperature homoepitaxial GaP films grown by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) have been studied. Smooth, stepped surface morphologies of MBE-grown layers, measured by atomic force microscopy, were found for a wide range of substrate temperatures and P{sub 2}:Ga flux ratios. A MOCVD-based growth study performed under similar conditions to MBE-grown samples shows a nearly identical smooth, step-flow surface morphology, presenting a convergence of growth conditions for the two different methods. The additional understanding of GaP epitaxy gained from this study will impact its use in applications that include GaP-based device technologies, III-V metamorphic buffers, and III-V materials integration with silicon.
Ratcliff, C. [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Grassman, T. J.; Ringel, S. A. [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Institute for Materials Research, Ohio State University, Columbus, Ohio 43210 (United States); Carlin, J. A. [Institute for Materials Research, Ohio State University, Columbus, Ohio 43210 (United States)
Atomic-level investigation of the growth of Si/Ge by ultrahigh vacuum chemical vapor deposition
Si and Ge films can be prepared under ultrahigh vacuum conditions by chemical vapor deposition using disilane and digermane as source gases. These gases offer a high sticking probability, and are suitable for atomic layer epitaxy. Using synchrotron radiation photoemission spectroscopy and scanning tunneling microscopy, we have examined the surface processes associated with the heteroepitaxial growth of Ge/Si. The measured surface-induced shifts and chemical shifts of the Si 2p and Ge 3d core levels allow us to identify the surface species and to determine the surface chemical composition, and this information is correlated with the atomic features observed by scanning tunneling microscopy. Issues related to precursor dissociation, attachment to dangling bonds, diffusion, surface segregation, growth morphology, and pyrolytic reaction pathways will be discussed. {copyright} {ital 1997 American Vacuum Society.}
Lin, D. [Institute of Physics, National Chiao-Tung University, Hsinchu, Taiwan, Republic of (China)] [Institute of Physics, National Chiao-Tung University, Hsinchu, Taiwan, Republic of (China); Miller, T.; Chiang, T. [Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)] [Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)
ZnO light-emitting diode grown by plasma-assisted metal organic chemical vapor deposition
We report a breakthrough in fabricating ZnO homojunction light-emitting diode by metal organic chemical vapor deposition. Using NO plasma, we are able to grow p-type ZnO thin films on n-type bulk ZnO substrates. The as-grown films on glass substrates show hole concentration of 10{sup 16}-10{sup 17} cm{sup -3} and mobility of 1-10 cm{sup 2} V{sup -1} s{sup -1}. Room-temperature photoluminescence spectra reveal nitrogen-related emissions. A typical ZnO homojunction shows rectifying behavior with a turn-on voltage of about 2.3 V. Electroluminescence at room temperature has been demonstrated with band-to-band emission at I=40 mA and defect-related emissions in the blue-yellow spectrum range.
Xu, W.Z.; Ye, Z.Z.; Zeng, Y.J.; Zhu, L.P.; Zhao, B.H.; Jiang, L.; Lu, J.G.; He, H.P.; Zhang, S.B. [State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
Method of chemical vapor deposition of boron nitride using polymeric cyanoborane
Polymeric cyanoborane is volatilized, decomposed by thermal or microwave plasma energy, and deposited on a substrate as an amorphous film containing boron, nitrogen and carbon. Residual carbon present in the film is removed by ammonia treatment at an increased temperature, producing an adherent, essentially stoichiometric boron nitride film.
Maya, Leon (Oak Ridge, TN)
Polymeric cyanoborane is volatilized, decomposed by thermal or microwave plasma energy, and deposited on a substrate as an amorphous film containing boron, nitrogen and carbon. Residual carbon present in the film is removed by ammonia treatment at an increased temperature, producing an adherent, essentially stoichiometric boron nitride film. 11 figs.
Maya, L.
Designing Turbine Endwalls for Deposition Resistance with 1,400 °C Combustor Exit Temperatures and Syngas Water Vapor LevelsThe Ohio State University
Designing Turbine Endwalls for Designing Turbine Endwalls for Deposition Resistance with 1,400 °C Combustor Exit Temperatures and Syngas Water Vapor Levels-The Ohio State University Background This University Turbine Systems Research (UTSR) project will explore a critical need for innovative turbine endwall designs that could increase turbine durability and mitigate the adverse effects of residue deposition from coal-derived synthesis gas (syngas). The Ohio State University (OSU), in cooperation with Brigham Young University (BYU),
Application to low-pressure deposition of tungsten
This paper reports on a mode for the simultaneous reaction kinetics and transport processes in chemical vapor deposition (CVD) reactors extended to treat deposition of materials that have a broad range of surface characteristics, e.g. sites with multiple dangling bonds and adsorbates with multiple bonding configurations. The model uses the nature of the surface to determine the elementary processes that can take place during growth. Rate constants for these processes are calculated from first principles using statistical thermodynamics, transition state theory, and bond dissociation enthalpies. In this way, deposition rates are determined without either assuming the reaction mechanism or arbitrarily choosing any kinetic parameter values. The utility of the approach is illustrated by modeling low-pressure CVD of tungsten from tungsten hexafluoride and hydrogen. The treatment considers 14 species and eight reactions in the gas together with 21 species and 65 processes at the surface.
Arora, R.; Pollard, R. (Dept. of Chemical Engineering, Univ. of Houston, Houston, TX (US))
The Progress on Low-Cost, High-Quality, High-Temperature Superconducting Tapes Deposited by the Combustion Chemical Vapor Deposition Process
The innovative Combustion Chemical Vapor Deposition (CCVD) process is a non-vacuum technique that is being investigated to enable next generation products in several application areas including high-temperature superconductors (HTS). In combination with the Rolling Assisted Biaxially Textured Substrate (RABiTS) technology, the CCVD process has significant promise to provide low-cost, high-quality lengths of YBCO coated conductor. Over 100 meter lengths of both Ni and Ni-W (3 at. Wt.%) substrates with a surface roughness of 12-18 nm were produced. The CCVD technology has been used to deposit both buffer layer coatings as well as YBCO superconducting layers. Buffer layer architecture of strontium titanate (SrTiO{sub 3}) and ceria (CeO{sub 2}) have been deposited by CCVD on textured nickel substrates and optimized to appropriate thicknesses and microstructures to provide templates for growing PLD YBCO with a J{sub c} of 1.1 MA/cm{sup 2} at 77 K and self-field. The CCVD buffer layers have been scaled to meter plus lengths with good epitaxial uniformity along the length. A short sample cut from one of the lengths enabled high critical current density PLD YBCO. Films of CCVD YBCO superconductors have been grown on single crystal substrates with critical current densities over 1 MA/cm{sup 2}. In addition, superconducting YBCO films with an I{sub c} of 60 A/cm-width (J{sub c} = 1.5 MA/cm{sup 2}) were grown on ORNL RABiTS (CeO{sub 2}/YSZ/Y{sub 2}O{sub 3}/Ni/Ni-3W) using CCVD process.
Shoup, S.S.; White, M.K.; Krebs, S.L.; Darnell, N.; King, A.C.; Mattox, D.S.; Campbell, I.H.; Marken, K.R.; Hong, S.; Czabaj, B.; Paranthaman, M.; Christen, H.M.; Zhai, H.-Y. Specht, E.
Thermal Stability and Substitutional Carbon Incorporation far above Solid-Solubility in Si1-xCx and Si1-x-yGexCy Layers Grown by Chemical Vapor Deposition
Cx and Si1-x-yGexCy Layers Grown by Chemical Vapor Deposition using Disilane M. S. Carroll*, J. C. Sturm on (100) silicon substrates by rapid thermal chemical vapor deposition (RTCVD) with disilane source gas and disilane is known to produce higher silicon epitaxial growth rates for similar partial
Quantum cascade laser investigations of CH{sub 4} and C{sub 2}H{sub 2} interconversion in hydrocarbon/H{sub 2} gas mixtures during microwave plasma enhanced chemical vapor deposition of diamond
CH{sub 4} and C{sub 2}H{sub 2} molecules (and their interconversion) in hydrocarbon/rare gas/H{sub 2} gas mixtures in a microwave reactor used for plasma enhanced diamond chemical vapor deposition (CVD) have been investigated by line-of-sight infrared absorption spectroscopy in the wavenumber range of 1276.5-1273.1 cm{sup -1} using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or Ne), input gas mixing ratio], height (z) above the substrate, and time (t) after addition of hydrocarbon to a pre-existing Ar/H{sub 2} plasma. The line integrated absorptions so obtained have been converted to species number densities by reference to the companion two-dimensional (r,z) modeling of the CVD reactor described in Mankelevich et al. [J. Appl. Phys. 104, 113304 (2008)]. The gas temperature distribution within the reactor ensures that the measured absorptions are dominated by CH{sub 4} and C{sub 2}H{sub 2} molecules in the cool periphery of the reactor. Nonetheless, the measurements prove to be of enormous value in testing, tensioning, and confirming the model predictions. Under standard process conditions, the study confirms that all hydrocarbon source gases investigated (methane, acetylene, ethane, propyne, propane, and butane) are converted into a mixture dominated by CH{sub 4} and C{sub 2}H{sub 2}. The interconversion between these two species is highly dependent on the local gas temperature and the H atom number density, and thus on position within the reactor. CH{sub 4}->C{sub 2}H{sub 2} conversion occurs most efficiently in an annular shell around the central plasma (characterized by 1400CH{sub 4} is favored in the more distant regions where T{sub gas}C{sub 2}H{sub 2} conversion, whereas the reverse C{sub 2}H{sub 2}->CH{sub 4} process only requires H atoms to drive the reactions; H atoms are not consumed by the overall conversion.
Ma Jie; Cheesman, Andrew; Ashfold, Michael N. R. [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Hay, Kenneth G.; Wright, Stephen; Langford, Nigel; Duxbury, Geoffrey [Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Mankelevich, Yuri A. [Skobel'tsyn Institute of Nuclear Physics, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)
AlGaN/GaN high electron mobility transistors based on InGaN/GaN multi-quantum-well structures with photo-chemical vapor deposition of SiO2 dielectrics
AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) based on InGaN/GaN multi-quantum-well (MQW) structure has been fabricated with SiO"2 dielectric deposited via photo-chemical vapor deposition (PHCVD) using a deuterium lamp ... Keywords: GaN, HEMT, MQW, Photo-chemical vapor deposition, SiO 2
Kai-Hsuan Lee; Ping-Chuan Chang; Shoou-Jinn Chang
Vapor deposition of thin-film Y-doped ZrO{sub 2} for electrochemical device applications
Solid oxide electrolytes based on yttria-stabilized zirconia (YSZ) are widely used in applications such as oxygen sensors, solid oxide fuel cells, oxygen pumps, electrocatalytic reactors, and electrochemically driven oxygen separation membranes. However, bulk YSZ is used in these applications. This requires high operating temperatures in order to minimize ohmic loss. One alternative of overcoming this problem is to use a thin film of the electrolyte. In the work, the authors have grown polycrystalline thin films of fully stabilized Y-ZrO{sub 2} on thick porous Al{sub 2}O{sub 3} substrates in multilayer La{sub 1{minus}x}Sr{sub x}MEO{sub 3}YSZ/La{sub 1{minus}x}Sr{sub x}MEO{sub 3} (ME = Mn, Co) configurations using a combination of single-target RF magnetron sputtering and electron beam physical vapor deposition techniques. The structure and morphology of these films have been studied using X-ray diffraction, and Scanning Electron Microscopy techniques. The ionic conductivity of the thin films has been measured using AC impedance analysis.
Chung, B.W.; Brosha, E.L.; Brown, D.R.; Garzon, F.H.
Activity and Evolution of Vapor Deposited Pt-Pd Oxygen Reduction Catalysts for Solid Acid Fuel Cells
The performance of hydrogen fuel cells based on the crystalline solid proton conductor CsH2PO4 is circumscribed by the mass activity of platinum oxygen reduction catalysts in the cathode. Here we report on the first application of an alloy catalyst in a solid acid fuel cell, and demonstrate an activity 4.5 times greater than Pt at 0.8 V. These activity enhancements were obtained with platinum-palladium alloys that were vapor-deposited directly on CsH2PO4 at 210 C. Catalyst mass activity peaks at a composition of 84 at% Pd, though smaller activity enhancements are observed for catalyst compositions exceeding 50 at% Pd. Prior to fuel cell testing, Pd-rich catalysts display lattice parameter expansions of up to 2% due to the presence of interstitial carbon. After fuel cell testing, a Pt-Pd solid solution absent of lattice dilatation and depleted in carbon is recovered. The structural evolution of the catalysts is correlated with catalyst de-activation.
Papandrew, Alexander B [ORNL; Chisholm, Calum R [ORNL; Zecevic, strahinja [LiOx, Inc., Pasadena, California 91106, United States; Veith, Gabriel M [ORNL; Zawodzinski, Thomas A [ORNL
Fundamental studies of the chemical vapor deposition of diamond. Final technical report, April 1, 1988--December 31, 1994
We submit here a final technical report for the research program entitled: Fundamental Studies of the Chemical Vapor Deposition of Diamond, DOE Grant No. DE-FG05-88ER45345-M006. This research program was initiated in 1988 under the direction of the late Professor David A. Stevenson and was renewed in 1992. Unfortunately, at the end of 1992, just as the last phase of this work was getting underway, Professor Stevenson learned that he had developed mesothelioma, a form of cancer based on asbestos. Professor Stevenson died from that disease in February of 1994. Professor William D. Nix, the Chairman of the Materials Science department at Stanford was named the Principal Investigator. Professor Nix has assembled this final technical report. Much of the work of this grant was conducted by Mr. Paul Dennig, a graduate student who will receive his Ph.D. degree from Stanford in a few months. His research findings are described in the chapters of this report and in the papers published over the past few years. The main discovery of this work was that surface topology plays a crucial role in the nucleation of diamond on silicon. Dennig and his collaborators demonstrated this by showing that diamond nucleates preferentially at the tips of asperities on a silicon surface rather than in the re-entrant comers at the base of such asperities. Some of the possible reasons for this effect are described in this report. The published papers listed on the next page of this report also describe this research. Interested persons can obtain copies of these papers from Professor Nix at Stanford. A full account of all of the research results obtained in this work is given in the regular chapters that follow this brief introduction. In addition, interested readers will want to consult Mr. Dennig`s Ph.D. dissertation when it is made available later this year.
Nix, W.D.
Calibrated vapor generator source
A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet.
Davies, John P. (Idaho Falls, ID); Larson, Ronald A. (Idaho Falls, ID); Goodrich, Lorenzo D. (Shelley, ID); Hall, Harold J. (Idaho Falls, ID); Stoddard, Billy D. (Idaho Falls, ID); Davis, Sean G. (Idaho Falls, ID); Kaser, Timothy G. (Idaho Falls, ID); Conrad, Frank J. (Albuquerque, NM)
A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet. 10 figs.
Davies, J.P.; Larson, R.A.; Goodrich, L.D.; Hall, H.J.; Stoddard, B.D.; Davis, S.G.; Kaser, T.G.; Conrad, F.J.
Vapor Deposition Processing
...R.D. Blaugher, High-Temperature Superconductors for Wires and TapesSuperconducting Materials, Vol 2, ASM Handbook,
Atmospheric Pressure Chemical Vapor Deposition of High Silica SiO2-TiO2 Antireflective Thin Films for Glass Based Solar Panels
The atmospheric pressure chemical vapor deposition (APCVD) of SiO2-TiO2 thin films employing [[(tBuO)3Si]2O-Ti(OiPr)2], which can be prepared from commercially available materials, results in antireflective thin films on float glass under industrially relevant manufacturing conditions. It was found that while the deposition temperature had an effect on the SiO2:TiO2 ratio, the thickness was dependent on the time of deposition. This study shows that it is possible to use APCVD employing a single source precursor containing titanium and silicon to produce thin films on float glass with high SiO2:TiO2 ratios.
Klobukowski, Erik R [ORNL; Tenhaeff, Wyatt E [ORNL; McCamy, James [PPG; Harris, Caroline [PPG; Narula, Chaitanya Kumar [ORNL
Method and system using power modulation for maskless vapor deposition of spatially graded thin film and multilayer coatings with atomic-level precision and accuracy
A method and system for producing a film (preferably a thin film with highly uniform or highly accurate custom graded thickness) on a flat or graded substrate (such as concave or convex optics), by sweeping the substrate across a vapor deposition source operated with time-varying flux distribution. In preferred embodiments, the source is operated with time-varying power applied thereto during each sweep of the substrate to achieve the time-varying flux distribution as a function of time. A user selects a source flux modulation recipe for achieving a predetermined desired thickness profile of the deposited film. The method relies on precise modulation of the deposition flux to which a substrate is exposed to provide a desired coating thickness distribution.
Montcalm, Claude (Livermore, CA); Folta, James Allen (Livermore, CA); Tan, Swie-In (San Jose, CA); Reiss, Ira (New City, NY)
Real-time, in situ film thickness metrology in a 10 Torr W chemical vapor deposition process using an acoustic sensor
analysis to establish a sensor model with an accuracy better than 1%. This was achieved in a 10 Torr W CVD achieving film thickness metrology with a 2% error using mass spectrometry or residual gas analysis scale Ulvac ERA 1000 W CVD cluster tool which is outfitted with water- cooled walls. The WF6 precursor
Study of plasma enhanced chemical vapor deposition of boron-doped hydrogenated amorphous silicon thin films and the application to p-channel thin film transistor
The material and process characteristics of boron doped hydrogenated amorphous silicon (a-Si:H) thin film deposited by plasma enhanced chemical vapor deposition technique (PECVD) have been studied. The goal is to apply the high quality films deposited at low substrate temperature for devices such as thin film transistors (TFTs). The effect of the deposition parameters such as doping gas concentration, substrate temperature, hydrogen dilution, helium dilution, power density, and pressure at 50 kHz rf frequency on the films' characteristics were analyzed. The films' electrical property was characterized by its dark resistivity. The chemical composition and bonding characteristics were discussed. p-channel TFTs were fabricated with these optimized films. Three different levels of dopant concentrations in the channel were used to detect the dopant effect on the TFT properties. Doping resulted in the increase of film deposition rate. The low film deposition rate at the high temperature deposition corresponds to a dense structured film. The increase of gas phase H? concentration could increase H? etching of the weak bonds in the film, which is consistent with the decrease of the deposition rate. Film's dark conductivity is determined by the atomic B concentration in the film, the substrate temperature, the ion bombardment effect, the surface morphology, and the gas phase and film hydrogen concentration. At high power density and high pressure plasma condition, film with a high deposition rate shows a high conductivity. However, excessive ion bombardment effect, e.g. in powdery plasma region, limits the further increase of the conductivity. Film deposited with He dilution demonstrates a higher conductivity compared to the H? dilution counterpart. This might be attributed to a more effective ion bombardment effect of the former. Powder generation in the plasma significantly affects the conductivity of He diluted film compared to the H? diluted ones, which might be due to the less H? etching effect at the He dilution deposition. The output and transfer characteristics show the normal p-channel TFTs behavior. TFT characteristics, such as mobility, threshold voltage, and on-off current ratio were affected by the doping gas concentration in the channel layer and the deposition process.
Nominanda, Helinda
The relationship between structural evolution and electrical percolation of the initial stages of tungsten chemical vapor deposition on polycrystalline TiN
This paper presents experimental results and a geometric model of the evolution of sheet resistance and surface morphology during the transition from nucleation to percolation of tungsten chemical vapor deposition over ultrathin polycrystalline titanium nitride (TiN). We observed two mechanisms of reduction in sheet resistance. At deposition temperatures higher than 310 deg. C, percolation effect is formed at {approx}35% of surface coverage, {theta}, and characterized with a sharp drop in resistance. At temperature below 310 deg. C, a reduction in resistance occurs in two steps. The first step occurs when {theta} = 35% and the second step at {theta} = 85%. We suggest a geometric model in which the electrical percolation pass is modulated by the thickness threshold of the islands at the instant of collision.
Rozenblat, A. [Micron Semiconductors Israel Ltd., Qiryat-Gat 82109 (Israel); Department of Physical Electronics, Electrical Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Haimson, S. [Material Science Program, Tel Aviv University, Tel Aviv 69978 (Israel); Shacham-Diamand, Y. [Department of Physical Electronics, Electrical Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Horvitz, D. [Micron Semiconductors Israel Ltd., Qiryat-Gat 82109 (Israel)
Use of SiBN and SiBON films prepared by plasma enhanced chemical vapor deposition from borazine as interconnection dielectrics
Thin films of silicon boron nitride (SiBN) of typical composition Si{sub 0.09}B{sub 0.39}N{sub 0.51} and silicon boron oxynitride (SiBON) of typical composition Si{sub 0.16}B{sub 0.29}O{sub 0.41}N{sub 0.14} were prepared by plasma enhanced chemical vapor deposition and the properties of these films were evaluated with respect to their suitability as interconnection dielectrics in microelectronic fabrication. Films were deposited on 125 mm silicon substrates in a parallel-plate reactor at a substrate temperature of 400 C and a plasma power of 0.5 W/cm{sup 2}. Boron nitride, for comparison of electrical properties, was deposited from borazine (B{sub 3}N{sub 3}H{sub 6}); silicon boron nitride was deposited from borazine, disilane (Si{sub 2}H{sub 6}), and ammonia (NH{sub 3}); silicon boron oxynitride was deposited from borazine, disilane, ammonia, and nitrous oxide (N{sub 2}O). Metal-insulator-metal capacitors were fabricated and electrical measurements indicated that all three films had excellent dielectric properties with dielectric constants of 4.1, 4.7, and 3.9 for BN, SiBN, and SiBON, respectively. Tests of conformality indicated that deposition into trenches with an aspect ratio of 4:1 gave conformality greater than 70%. Silicon boron oxynitride was shown to be an excellent barrier to the diffusion of copper. A planar, single level metal-insulator structure was constructed using a SiBN/SiBON insulator with copper metallization.
Kane, W.F.; Cohen, S.A.; Hummel, J.P.; Luther, B. [IBM Research Div., Yorktown Heights, NY (United States). T.J. Watson Research Center; Beach, D.B. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.
Available Technologies: Catalyst Patterning for Scalable CVD ...
Nano- & Micro-technology; Software and IT ; Licensing Interest Form Receive Customized Tech Alerts. Catalyst Patterning for Scalable CVD Growth of Graphene Nanoribbon.
The use of electron channeling patterns for process optimization of low-temperature epitaxial silicon using hot-wire chemical vapor deposition
The authors demonstrate the first reported use of electron channeling patterns (ECPs) as a response for a statistical design of experiments process-optimization for epitaxial silicon. In an effort to fully characterize the new hot-wire chemical vapor deposition (HWCVD) method of epitaxial growth recently discovered at NREL, a large number of parameters with widely varying values needed to be considered. To accomplish this, they used the statistical design of experiments method. This technique allows one to limit the number of sample points necessary to evaluate a given parameter space. In this work they demonstrate how ECPs can effectively be used to optimize the process space as well as to quickly and economically provide the process engineer with absolutely key information.
Matson, R.; Thiesen, J.; Jones, K.M.; Crandall, R.; Iwaniczko, E.; Mahan, H.
Direct growth of few-layer graphene on 6H-SiC and 3C-SiC/Si via propane chemical vapor deposition
We propose to grow graphene on SiC by a direct carbon feeding through propane flow in a chemical vapor deposition reactor. X-ray photoemission and low energy electron diffraction show that propane allows to grow few-layer graphene (FLG) on 6H-SiC(0001). Surprisingly, FLG grown on (0001) face presents a rotational disorder similar to that observed for FLG obtained by annealing on (000-1) face. Thanks to a reduced growth temperature with respect to the classical SiC annealing method, we have also grown FLG/3C-SiC/Si(111) in a single growth sequence. This opens the way for large-scale production of graphene-based devices on silicon substrate.
Michon, A.; Vezian, S.; Portail, M. [CNRS-CRHEA, Rue Bernard Gregory, 06560 Valbonne (France); Ouerghi, A. [CNRS-LPN, Route de Nozay, 91460 Marcoussis (France); Zielinski, M.; Chassagne, T. [NOVASiC, Savoie Technolac, Arche Bat 4, BP267, 73375 Le Bourget du Lac (France)
The Effect of Growth Parameters on the Intrinsic Properties of Large-Area Single Layer Graphene Grown by Chemical Vapor Deposition on Cu
We present a comprehensive study of the parameter space for single layer graphene growth by chemical vapor deposition on Cu. The temperature is the most widely recognized parameter in single layer graphene growth. We show that the methane-to-hydrogen ratio and the growth pressure also are critical parameters that affect the structural perfection and the cleanliness of graphene. The optimal conditions for suppressing double and multilayer graphene growth occur near 1000 C, 1:20 methane-to-hydrogen ratio, and a total pressure in the range from 0.5 to 1 Torr. Raman mapping of a 40x30 m2 area shows single layer domains with 5-10 m linear dimensions. Atomic resolution imaging of suspended graphene by aberration corrected scanning transmission electron microscopy shows that the cleanest single layer graphene consists of areas of 10-15 nm linear dimensions and smaller patches of residual contamination that was undetected by other characterization methods.
Regmi, Murari [ORNL; Chisholm, Matthew F [ORNL; Eres, Gyula [ORNL
As-grown deep-level defects in n-GaN grown by metal-organic chemical vapor deposition on freestanding GaN
Traps of energy levels E{sub c}-0.26 and E{sub c}-0.61 eV have been identified as as-grown traps in n-GaN grown by metal-organic chemical vapor deposition by using deep level transient spectroscopy of the Schottky contacts fabricated by resistive evaporation. The additional traps of E{sub c}-0.13 and E{sub c}-0.65 eV have been observed in samples whose contacts are deposited by electron-beam evaporation. An increase in concentration of the E{sub c}-0.13 and E{sub c}-0.65 eV traps when approaching the interface between the contact and the GaN film supports our argument that these traps are induced by electron-beam irradiation. Conversely, the depth profiles of as-grown traps show different profiles between several samples with increased or uniform distribution in the near surface below 50 nm. Similar profiles are observed in GaN grown on a sapphire substrate. We conclude that the growth process causes these large concentrations of as-grown traps in the near-surface region. It is speculated that the finishing step in the growth process should be an essential issue in the investigation of the surface state of GaN.
Chen Shang; Ishikawa, Kenji; Hori, Masaru [Nagoya University, Chikusa, Nagoya 464-8603 (Japan); Honda, Unhi; Shibata, Tatsunari; Matsumura, Toshiya; Tokuda, Yutaka [Aichi Institute of Technology, Yakusa, Toyota 470-0392 (Japan); Ueda, Hiroyuki; Uesugi, Tsutomu; Kachi, Tetsu [Toyota Central R and D Laboratories, Inc., Yokomichi, Nagakute 480-1192 (Japan)
Measurement of surface acidity by [sup 31]P NMR of adsorbed trimethylphosphine: Application to vapor deposited SiO[sub 2] on Al[sub 2]O[sub 3] monolayer catalysts
Experimental procedures for quantitative estimation of surface acid by [sup 31]P NMR of adsorbed phosphines are discussed. These procedures are illustrated by application to a commercial silica alumina cracking catalyst, and are applied to a series of silica on alumina monolayer catalysts prepared by chemical vapor deposition. The monolayer catalysts show a maximum in Broensted acidity for a deposition of 8 SiO[sub 2] groups per nm[sup 2] of Al[sub 2]O[sub 3] surface. The evolution of Broensted acid concentration as a function of amount of deposited silica can be accounted for by a simple kinetic model. 9 refs., 5 figs., 2 tabs
Sheng, Tai-Cheng (Shandong Univ. (China)); Gay, I.D. (Simon Fraser Univ., British Columbia (Canada))
Issues associated with the metalorganic chemical vapor deposition of ScGaN and YGaN alloys.
The most energy efficient solid state white light source will likely be a combination of individually efficient red, green, and blue LED. For any multi-color approach to be successful the efficiency of deep green LEDs must be significantly improved. While traditional approaches to improve InGaN materials have yielded incremental success, we proposed a novel approach using group IIIA and IIIB nitride semiconductors to produce efficient green and high wavelength LEDs. To obtain longer wavelength LEDs in the nitrides, we attempted to combine scandium (Sc) and yttrium (Y) with gallium (Ga) to produce ScGaN and YGaN for the quantum well (QW) active regions. Based on linear extrapolation of the proposed bandgaps of ScN (2.15 eV), YN (0.8 eV) and GaN (3.4 eV), we expected that LEDs could be fabricated from the UV (410 nm) to the IR (1600 nm), and therefore cover all visible wavelengths. The growth of these novel alloys potentially provided several advantages over the more traditional InGaN QW regions including: higher growth temperatures more compatible with GaN growth, closer lattice matching to GaN, and reduced phase separation than is commonly observed in InGaN growth. One drawback to using ScGaN and YGaN films as the active regions in LEDs is that little research has been conducted on their growth, specifically, are there metalorganic precursors that are suitable for growth, are the bandgaps direct or indirect, can the materials be grown directly on GaN with a minimal defect formation, as well as other issues related to growth. The major impediment to the growth of ScGaN and YGaN alloys was the low volatility of metalorganic precursors. Despite this impediment some progress was made in incorporation of Sc and Y into GaN which is detailed in this report. Primarily, we were able to incorporate up to 5 x 10{sup 18} cm{sup -3} Y atoms into a GaN film, which are far below the alloy concentrations needed to evaluate the YGaN optical properties. After a no-cost extension was granted on this program, an additional more 'liquid-like' Sc precursor was evaluated and the nitridation of Sc metals on GaN were investigated. Using the Sc precursor, dopant level quantities of Sc were incorporated into GaN, thereby concluding the growth of ScGaN and YGaN films. Our remaining time during the no-cost extension was focused on pulsed laser deposition of Sc metal films on GaN, followed by nitridation in the MOCVD reactor to form ScN. Finally, GaN films were deposited on the ScN thin films in order to study possible GaN dislocation reduction.
Koleske, Daniel David; Knapp, James Arthur; Lee, Stephen Roger; Crawford, Mary Hagerott; Creighton, James Randall; Cross, Karen Charlene; Thaler, Gerald
Low temperature metal-organic chemical vapor deposition growth processes for high-efficiency solar cells. Final technical report, 1 September 1985--30 November 1989
Dapkus, P.D. [University of Southern California, Los Angeles, CA (United States)
Process for depositing hard coating in a nozzle orifice
The present invention is directed to a process for coating the interior surfaces of an orifice in a substrate that forms a slurry fuel injection nozzle. In a specific embodiment, the nozzle is part of a fuel injection system for metering a coal-water slurry into a large, medium-speed, multi-cylinder diesel engine. In order to retard erosion of the orifice, the substrate is placed in a chemical vapor deposition (CVD) reaction chamber. A reaction gas is passed into the chamber at a gas temperature below its reaction temperature and is directed through the orifice in the substrate. The gas reaction temperature is a temperature at and above which the reaction gas deposits as a coating, and the reaction gas is of a composition whereby improved resistance to erosion by flow of the particulates in the slurry fuel is imparted by the deposited coating. Only the portion of the substrate in proximity to the orifice to be coated is selectively heated to at least the gas reaction temperature for effecting coating of the orifice's interior surfaces by the vapor deposited coating formed from the reaction gas. 2 figures.
Flynn, P.L.; Giammarise, A.W.
Apparatus for depositing hard coating in a nozzle orifice
The present invention is directed to a process for coating the interior surfaces of an orifice in a substrate that forms a slurry fuel injection nozzle. In a specific embodiment, the nozzle is part of a fuel injection system for metering a coal-water slurry into a large, medium-speed, multi-cylinder diesel engine. In order to retard erosion of the orifice, the substrate is placed in a chemical vapor deposition (CVD) reaction chamber. A reaction gas is passed into the chamber at a gas temperature below its reaction temperature and is directed through the orifice in the substrate. The gas reaction temperature is a temperature at and above which the reaction gas deposits as a coating, and the reaction gas is of a composition whereby improved resistance to erosion by flow of the particulates in the slurry fuel is imparted by the deposited coating. Only the portion of the substrate in proximity to the orifice to be coated is selectively heated to at least the gas reaction temperature for effecting coating of the orifice`s interior surfaces by the vapor deposited coating formed from the reaction gas. 2 figs.
The present invention is directed to a process for coating the interior surfaces of an orifice in a substrate that forms a slurry fuel injection nozzle. In a specific embodiment, the nozzle is part of a fuel injection system for metering a coal-water slurry into a large, medium-speed, multi-cylinder diesel engine. In order to retard erosion of the orifice, the substrate is placed in a chemical vapor deposition (CVD) reaction chamber. A reaction gas is passed into the chamber at a gas temperature below its reaction temperature and is directed through the orifice in the substrate. The gas reaction temperature is a temperature at and above which the reaction gas deposits as a coating, and the reaction gas is of a composition whereby improved resistance to erosion by flow of the particulates in the slurry fuel is imparted by the deposited coating. Only the portion of the substrate in proximity to the orifice to be coated is selectively heated to at least the gas reaction temperature for effecting coating of the orifice's interior surfaces by the vapor deposited coating formed from the reaction gas.
Flynn, Paul L. (Fairview, PA); Giammarise, Anthony W. (Erie, PA)
The present invention is directed to a process for coating the interior surfaces of an orifice in a substrate that forms a slurry fuel injection nozzle. In a specific embodiment, the nozzle is part of a fuel injection system for metering a coal-water slurry into a large, medium-speed, multi-cylinder diesel engine. In order to retard erosion of the orifice, the substrate is placed in a chemical vapor deposition (CVD) reaction chamber. A reaction gas is passed into the chamber at a gas temperature below its reaction temperature and is directed through the orifice in the substrate. The gas reaction temperature is a temperature at and above which the reaction gas deposits as a coating, and the reaction gas is of a composition whereby improved resistance toerosion by flow of the particulates in the slurry fuel is imparted by the deposited coating. Only the portion of the substrate in proximity to the orifice to be coated is selectively heated to at least the gas reaction temperature for effecting coating of the orifice's interior surfaces by the vapor deposited coating formed from the reaction gas.
Flynn, Paul L. (5139 Fox Park Dr., Fairview, PA 16415); Giammarise, Anthony W. (527 Lincoln Ave., Erie, PA 16505)
Precursor chemistry for ULK CVD
Deposited thin silicon-based films used for electronic devices as insulators in interconnections should have low and ultra low permittivity (ULK) to be acceptable to the future integration requirements, especially for the advanced technology (45nm and ... Keywords: PECVD, Porogens, Silicon-based precursors, ULK materials
V. Rouessac; L. Favennec; B. R�miat; V. Jousseaume; G. Passemard; J. Durand
Principles of Chemical Vapor Deposition
...as well as the fluid dynamic aspects of the reactor system, to improve process efficiency. Many computational
Dielectric properties of chemically vapour-deposited Si 3 N 4
measured by using a transformer bridge (Ando; TR-. 10C). ..... TABLE I Deposition conditions and some properties of CVD-Si3N 4. Specimen. Tdep*. P,
Characterization of photoluminescent (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3} thin-films prepared by metallorganic chemical vapor deposition
Europium doped yttrium oxide, (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3}, thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y{sub 2}O{sub 3}, grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y{sub 2}O{sub 3}:Eu{sup 3+} was observed in x-ray diffraction for deposition temperatures {ge}600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra.
McKittrick, J.; Bacalski, C.F.; Hirata, G.A. [Univ. of California, San Diego, La Jolla, CA (United States); Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.
Transport studies on CVD-grown graphene
In this thesis, we report transport studies performed on CVD-grown graphene. We perform resistivity and hall measurements on a large-area sample at 4' K. We measure the carrier mobility of the sample and find it to be on ...
Huntley, Miriam Hanna
Vapor Degreasing
Table 6 Applications of vapor degreasing by vapor-spray-vapor systems...hardware Brass 2270 5000 Buffing compound; rouge Lacquer spray Racked work on continuous monorail Acoustic ceiling tile Steel 2720 6000 Light oil (stamping lubricant) Painting Monorail conveyor Gas meters Terneplate 4540 10,000 Light oil Painting Monorail conveyor Continuous strip, 0.25�??4.1 mm...
Vapor Characterization
... thermodynamics (that is, vapor liquid equilibrium) as ... of solids and low volatility liquids is extraordinarily ... such situations is the gas saturation method ...
Apparatus and process for depositing hard coating in a nozzle orifice
Thermodynamic analysis and kinetic implications of chemical vapor deposition of SiC from Si-C-Cl-H gas systems
Experimental results compiled from the literature were compared to thermodynamic calculations of the most stable proportion of condensed phases to deposit from gas mixtures of Si-C-Cl-H. The calculations indicated that the predominant gas molecules participating in a deposition process are chlorides and chlorosilanes for silicon and methane and acetylene for carbon. The mismatch of the calculated and experimentally determined phase boundaries at 1473 and 1600 K led to the conclusion that silicon deposition occurs faster than carbon deposition in proportion to their partial pressures. The probable reason is that silicon-bearing gas molecules have a greater sticking probability on polar Si and SiC surfaces because of their asymmetric geometries. 18 references, 8 figures, 3 tables.
Fischman, G.S.; Petuskey, W.T.
Nano Pulse Second DC Pulsed Discharge for Plasma CVD Method
Plasma irradiated by metal-organic complexes, we can synthesize a thin film of metal or ceramic. However, the plasma CVD in the general law, sometimes high �...
Aerogel composites using chemical vapor infiltration
Aerogel composites using chemical vapor infiltration Aerogel composites using chemical vapor infiltration Title Aerogel composites using chemical vapor infiltration Publication Type Journal Article Year of Publication 1995 Authors Hunt, Arlon J., Michael R. Ayers, and Wanqing Cao Journal Journal of Non-Crystalline Solids Volume 185 Pagination 227-232 Abstract A new method to produce novel composite materials based on the use of aerogels as a starting material is described. Using chemical vapor infiltration, a variety of solid materials were thermally deposited into the open pore structure of aerogel. The resulting materials possess new and unusual properties including photoluminescence, magnetism and altered optical properties. An important characteristic of this preparation process is the very small size of the deposits that gives rise to new behaviors. Silicon deposits exhibit photoluminescence, indicating quantum confinement. Two or more phases may be deposited simultaneously and one or both chemically or thermally reacted to produce new structures.
Chemical vapor infiltration using microwave energy
This invention is comprised of a method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.
Devlin, D.J.; Currier, R.P.; Laia, J.R.; Barbero, R.S.
Fundamental studies of defect generation in amorphous silicon alloys grown by remote plasma-enhanced chemical-vapor deposition (Remote PECVD)
We demonstrated that the remote PECVD process can be used to deposit heavily doped n-type and p-type a-Si:H thin films. We optimized conditions for depositing undoped, near-intrinsic and heavily doped thin films of [mu]c(microcrystalline)-Si by remote PECVD. We extended the remote PECVD process to the deposition of undoped and doped a-Si,C:H and [mu]c-Si,C alloy films. We analyzed transport data for the dark conductivity in undoped and doped a-Si:H, a-Si,C:H, [mu]c-Si and [mu]c-Si,C films. We studied the properties of doped a-Si:H and [mu]c-Si in MOS capacitors using [approximately]10 [Omega]-cm p-type crystalline substrates and thermally grown Si0[sub 2] dielectric layers. We collaborated with a group at RWTH in Aachen, Germany, and studied the contributions of process induced defect states to the recombination of photogenerated electron pairs. We applied a tight-binding model to Si-Bethe lattice structures to investigate the effects of bond angle, and dihedral angle disorder. We used ab initio and empirical calculations to study non-random bonding arrangements in a-Si,O:H and doped a-Si:H films.
Lucovsky, G.; Nemanich, R.J.; Bernholc, J.; Whitten, J.; Wang, C.; Davidson, B.; Williams, M.; Lee, D.; Bjorkman, C.; Jing, Z. (North Carolina State Univ., Raleigh, NC (United States))
A New Centrifuge CVD Reactor that will Challenge the Siemens ...
In this presentation, results from the new centrifuge CVD reactor along with two other ... Boron Removal from Silicon Melts by H2O/H2 Gas Blowing � Gas-phase
Annealed CVD molybdenum thin film surface
Molybdenum thin films deposited by pyrolytic decomposition of Mo(CO).sub.6 attain, after anneal in a reducing atmosphere at temperatures greater than 700.degree. C., infrared reflectance values greater than reflectance of supersmooth bulk molybdenum. Black molybdenum films deposited under oxidizing conditions and annealed, when covered with an anti-reflecting coating, approach the ideal solar collector characteristic of visible light absorber and infrared energy reflector.
Carver, Gary E. (Tucson, AZ); Seraphin, Bernhard O. (Tucson, AZ)
Adsorption of TiCl[sub 4], SiH[sub 4], and HCl on Si(100): Application to TiSi[sub 2] chemical vapor deposition and Si etching
The interactions of TiCl[sub 4], SiH[sub 4], and HCl with Si(100) have been investigated by temperature programmed desorption (TPD) with the goal of better understanding the initial stages of TiSi[sub 2] chemical vapor deposition for circuit metallization and wafer etching with HCl/H[sub 2]. Coadsorption experiments with TiCl[sub 4] and SiH[sub 4] show that under most conditions H[sub 2] and SiCl[sub 2] are the main desorption products, with Ti being left behind on the surface. HCl is a minor product. However, at sufficiently low exposures of either TiCl[sub 4] or SiH[sub 4], the desorption of SiCl[sub 2] or H[sub 2], respectively, is inhibited in favor of HCl. A kinetic model involving formation of an HCl complex at defects has been formulated which explains the results quantitatively. HCl adsorption gives rise to the principal desorption products SiCl[sub 2] and H[sub 2], with HCl as a minor product. The kinetic behavior can also be explained quantitatively with the proposed model. Implications for TiSi[sub 2] growth are discussed with reference to possible growth temperatures and source gas pressures. The mechanism for etching by HCl is further elucidated.
Mendicino, M.A.; Seebauer, E.G. (Univ. of Illinois, Urbana, IL (United States). Dept. of Chemical Engineering)
Microwave Plasma Chemical Vapor Deposition of Carbon Coatings on LiNi1/3Co1/3Mn1/3O2 for Li-Ion Battery Composite Cathodes
In this paper, we report results of a novel synthesis method of thin film conductive carbon coatings on LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} cathode active material powders for lithium-ion batteries. Thin layers of graphitic carbon were produced from a solid organic precursor, anthracene, by a one-step microwave plasma chemical vapor deposition (MPCVD) method. The structure and morphology of the carbon coatings were examined using SEM, TEM, and Raman spectroscopy. The composite LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} electrodes were electrochemically tested in lithium half coin cells. The composite cathodes made of the carbon-coated LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} powder showed superior electrochemical performance and increased capacity compared to standard composite LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} electrodes.
Doeff, M.M.; Kostecki, R.; Marcinek, M.; Wilcoc, J.D.
A New Type of Microstructural. Instability in Superalloys - SRZ
deposited in a small chemical vapor deposition (CVD) reactor with a 6� x 12� hot ..... theory, there is an inittal rapid decrease in Re segregation followed by a.
Microwave plasma chemical vapor deposition of nano ...
radiation was also applied for rapid heating of solutions ... of the system was designed to generate Ar ... model JEOL 200CX), and scanning electron ...
High Efficiency and High Rate Deposited Amorphous Silicon-Based Solar Cells
of a triple cell showing 10.7% stable efficiency. Figure 4-1 Schematic diagram of the Hot Wire CVD deposition. Task 7: High-rate deposition of a-Si based solar cells We have conducted extensive research using a hot1 High Efficiency and High Rate Deposited Amorphous Silicon-Based Solar Cells PHASE I Annual
Deng, Xunming
Plasma-assisted CVD of fluorinated, hydrogenated amorphous silicon. Final report
During the past year, three novel large-area (100 cm/sup 2/) a-Si:H solar cells were developed with the following configurations: inverted NIP/SS cells with an improved red response; inverted a-Si:H/a-B:H heterojunction cells with high V/sub oc/; and NIP/metal cells with a CVD P-layer grown pyrolytically from silane and diborane. Initial experiments were performed using disilane as the deposition gas for the intrinsic layer in both NIP/SS and PIN/SS structures. Coatings of In/sub 2/O/sub 3/, using a technique developed by Dr. Ovadyahu, were applied to NIP/SS cells in order to evaluate its potential as a conductive coating in practical amorphous silicon solar cells.
Coleman, J.H.; Hammes, J.P.; Wiesmann, H.J.
Heterogeneous reaction mechanisms and kinetics relevant to the CVD of semiconductor materials
This report documents the state of the art in experimental and theoretical techniques for determining reaction mechanisms and chemical kinetics of heterogeneous reactions relevant to the chemical vapor deposition of semiconductor materials. It summarizes the most common ultra-high vacuum experimental techniques that are used and the types of rate information available from each. Several case studies of specific chemical systems relevant to the microelectronics industry are described. Theoretical methods for calculating heterogeneous reaction rate constants are also summarized.
Creighton, J.R.; Coltrin, M.E.
Mercury Vapor Pressure Correlation
An apparent difference between the historical mercury vapor concentration equations used by the mercury atmospheric measurement community ...
A reaction mechanism for titanium nitride CVD from TiCl{sub 4} and NH{sub 3}
A gas-phase and surface reaction mechanism for the CVD of TiN from TiCl{sub 4} and NH{sub 3} is proposed. The only gas-phase process is complex formation, which can compete with deposition. The surface mechanism postulates the stepwise elimination of Cl and H atoms from TiCl{sub 4} and NH{sub 3}, respectively, to form solid TiN and gaseous HCl. The mechanism also accounts for the change in oxidation state of Ti by allowing for liberation of N{sub 2}. Provided that the surface composition is at steady state, the stoichiometry of the overall reaction is reproduced exactly. In addition, the global kinetic law predicted by the mechanism is successfully fit to new deposition data from a rotating disk reactor and is shown to be consistent with literature results.
Larson, R.S.; Allendorf, M.D.
CVD apparatus and process for the preparation of fiber-reinforced ceramic composites
An apparatus and process for the chemical vapor deposition of a matrix into a preform having circumferentially wound ceramic fibers, comprises heating one surface of the preform while cooling the other surface thereof. The resulting product may have fibers that are wound on radial planes or at an angle from the radial planes. The fibers can also be precoated with pyrolytic carbon before application of the matrix. The matrix is applied by passing reactant gas through the preform thereof to the other side thereof for the initial deposition of matrix near such other surface of the preform. The matrix fills in the preform from the other side surface thereof to the surface of the side of application thereof until a desired amount of matrix has been deposited.
Caputo, Anthony J. (Knoxville, TN); Devore, Charles E. (Knoxville, TN); Lowden, Richard A. (Powell, TN); Moeller, Helen H. (Concord, VA)
Structural properties of Zn-ZnO core-shell microspheres grown by hot-filament CVD technique
We report the hot-filament chemical vapor deposition (HFCVD) growth of Zn-ZnO core-shell microspheres in the temperature range of 350-650�C only using ZnO pellets as raw material. The samples were characterized by scanning electron microscope (SEM), ...
R. L�pez; T. D�az; G. Garc�a; R. Galeazzi; E. Rosendo; A. Coyopol; M. Pacio; H. Ju�rez; A. I. Oliva
Vapor spill monitoring method
Method for continuous sampling of liquified natural gas effluent from a spill pipe, vaporizing the cold liquified natural gas, and feeding the vaporized gas into an infrared detector to measure the gas composition. The apparatus utilizes a probe having an inner channel for receiving samples of liquified natural gas and a surrounding water jacket through which warm water is flowed to flash vaporize the liquified natural gas.
Bianchini, Gregory M. (Livermore, CA); McRae, Thomas G. (Livermore, CA)
PPP Equipment Corporation | Open Energy Information
PPP Equipment Corporation Sector Solar Product PPP-E designs, produces and markets Chemical Vapor Deposition (CVD) reactors and converter systems producing high-purity...
CNST NanoFab Equipment - Furnaces/CVD
... Applications: Tube 1 (T1), open for future upgrade. Silicon Nitride Deposition (Tube 2): Low Stress recipe. Stoichiometric recipe. ...
Microwave plasma assisted supersonic gas jet deposition of thin film materials
An apparatus for fabricating thin film materials utilizing high speed gas dynamics relies on supersonic free jets of carrier gas to transport depositing vapor species generated in a microwave discharge to the surface of a prepared substrate where the vapor deposits to form a thin film. The present invention generates high rates of deposition and thin films of unforeseen high quality at low temperatures.
Schmitt, III, Jerome J. (New Haven, CT); Halpern, Bret L. (Bethany, CT)
Fundamental studies of defect generation in amorphous silicon alloys grown by remote plasma-enhanced chemical-vapor deposition (Remote PECVD). Annual subcontract report, 1 September 1990--31 August 1991
We demonstrated that the remote PECVD process can be used to deposit heavily doped n-type and p-type a-Si:H thin films. We optimized conditions for depositing undoped, near-intrinsic and heavily doped thin films of {mu}c(microcrystalline)-Si by remote PECVD. We extended the remote PECVD process to the deposition of undoped and doped a-Si,C:H and {mu}c-Si,C alloy films. We analyzed transport data for the dark conductivity in undoped and doped a-Si:H, a-Si,C:H, {mu}c-Si and {mu}c-Si,C films. We studied the properties of doped a-Si:H and {mu}c-Si in MOS capacitors using {approximately}10 {Omega}-cm p-type crystalline substrates and thermally grown Si0{sub 2} dielectric layers. We collaborated with a group at RWTH in Aachen, Germany, and studied the contributions of process induced defect states to the recombination of photogenerated electron pairs. We applied a tight-binding model to Si-Bethe lattice structures to investigate the effects of bond angle, and dihedral angle disorder. We used ab initio and empirical calculations to study non-random bonding arrangements in a-Si,O:H and doped a-Si:H films.
Lucovsky, G.; Nemanich, R.J.; Bernholc, J.; Whitten, J.; Wang, C.; Davidson, B.; Williams, M.; Lee, D.; Bjorkman, C.; Jing, Z. [North Carolina State Univ., Raleigh, NC (United States)
Plasma-assisted CVD of fluorinated, hydrogenated amorphous silicon. Final technical report, September 15, 1979-September 15, 1980
During the past year, approximately 300 large-area (400 cm/sup 2/) PIN hydrogenated amorphous silicon (a-Si:H) solar cells were fabricated and tested. a-Si:H PIN cells which were plasma deposited at 200/sup 0/ to 350/sup 0/ were found to have high internal currents (13mA/cm/sup 2/), whereas those which were deposited by CVD at 500/sup 0/ to 650/sup 0/C had low internal currents. When corrected for optical losses in the top electrode, the internal quantum efficiency vs wavelength for the PIN cells indicated a peak value above 80% at about 525nm, which decreased monotonically to zero at about 725 nm. When the published values of RCA and EXXON were corrected similarly for optical loss, nearly identical values of internal quantum efficiencies were found. Calculations based on a model proposed by Cody et al of EXXON indicated that the depletion width was less than 0.4 microns for all PIN cells, thereby limiting junction efficiency in the red portion of the solar spectrum since the 1/e photon range exceeds this value. A novel inverted NIP cell was tested and found to have its maximum quantum response shifted to 625 nm. Also, an amorphous boron (a-B) layer deposited on a-Si:H to form a PIN heterojunction improved blue response and Voc. A combination of the red-responsive cells and the a-B heterojunction cells could raise efficiency to 8%.
Coleman, J. H.; Hammes, J. P.; Wiesmann, H. J.
New novel cleaning technique for extending mean time between mechanical cleans in a Genus tungsten CVD reactor
During the chemical vapor deposition of blanket tungsten from the reduction of tungsten hexafluoride (WF{sub 6}), metallic parts within the reaction chamber accumulate metallic tungsten, tungsten oxyfluorides, and other related tungsten species. The usual method for removal of the chamber deposits is to open the chamber and perform a labor intensive mechanical clean, which involves the use of hydrogen peroxide (H{sub 2}O{sub 2}) and deionized (DI) water, or an in-situ fluorine-base plasma clean. The authors have investigated the use of repetitive in-situ nitrogen trifluoride (NF{sub 3}) plasma cleans during the course of operating a Genuse 8721 tungsten chemical vapor deposition reactor. The Genuse reactor has been retrofitted with self-ratchetting linear slides, which allow the wafer clamps to be extended into the NF{sub 3} plasma. They have extended the mean time between failures (MTBF) due to the use of 10 minute plasma clean every 75--100 wafers. Deposition for this process is 8,000 angstroms per wafer, using 6 deposition sites. The total tungsten deposition for a 0.5 micron tungsten plug is 4 microns, per a 25 wafer lot. Instead of a total removal of the accumulated tungsten from the chamber hardware, a partial etchback of the deposition from the wafer clamps and wafer chucks was performed. With this, sources for particles and backside deposition were eliminated. They see an increase in wafer-to-wafer uniformity, lot-to-lot repeatability, and particle reduction due to the use of frequent plasma clean. Recovery time after a plasma clean is excellent and no detrimental effects from hydrogen fluoride ``poisoning`` were seen.
Lujan, R.D.; Fleming, J.G.; Baird, J.L.; Gentry, M.S. [Sandia National Labs., Albuquerque, NM (United States). Center for Microelectronics Technologies
Simulations of CVD Diamond Film Growth Using a Simplified Monte Carlo Model Paul W. May1
, low energy, efficient process that stops the build up of polymer chains on the growing surface, medical coatings and optics [1]. The CVD process involves the gas phase decomposition of a gas mixture
Bristol, University of
Electrolyte vapor condenser
A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.
Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.
A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.
Sederquist, Richard A. (Newington, CT); Szydlowski, Donald F. (East Hartford, CT); Sawyer, Richard D. (Canton, CT)
Vapor concentration monitor
An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.
Bayly, John G. (Deep River, CA); Booth, Ronald J. (Deep River, CA)
Including Surface Kinetic Effects in Simple Models of Ice Vapor Diffusion
A model for kinetically-limited vapor growth and aspect ratio evolution of atmospheric single ice crystals is presented. The method is based on the adaptive habit model of Chen and Lamb (1994), but is modified to include the deposition ...
Chengzhu Zhang; Jerry Y. Harrington
Definition: Mercury Vapor | Open Energy Information
Mercury Vapor Jump to: navigation, search Dictionary.png Mercury Vapor Mercury is discharged as a highly volatile vapor during hydrothermal activity and high concentrations in...
Organic vapor jet printing system
An organic vapor jet printing system includes a pump for increasing the pressure of an organic flux.
Forrest, Stephen R
Mercury Vapor | Open Energy Information
Mercury Vapor Mercury Vapor Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Mercury Vapor Details Activities (23) Areas (23) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Fluid Lab Analysis Parent Exploration Technique: Fluid Lab Analysis Information Provided by Technique Lithology: Stratigraphic/Structural: Anomalously high concentrations can indicate high permeability or conduit for fluid flow Hydrological: Field wide soil sampling can generate a geometrical approximation of fluid circulation Thermal: High concentration in soils can be indicative of active hydrothermal activity Dictionary.png Mercury Vapor: Mercury is discharged as a highly volatile vapor during hydrothermal
Fuel vapor canister
This paper discusses an improved fuel vapor storage canister for use in a vehicle emission system of the type utilizing an enclosure with an interior communicated with a source of fuel vapor. The improved canister comprises: the enclosure having a mixture including particles of activated charcoal and many pieces of foam rubber, the pieces of foam rubber in the mixture being randomly and substantially evenly dispersed whereby substantially all the charcoal particles are spaced relatively closely to at least one foam rubber piece; the mixture being packed into the enclosure under pressure so that the pieces of foam rubber are compressed enough to tightly secure the charcoal particles one against another to prevent a griding action therebetween.
Moskaitis, R.J.; Ciuffetelli, L.A.
Stratified vapor generator
A stratified vapor generator (110) comprises a first heating section (H.sub.1) and a second heating section (H.sub.2). The first and second heating sections (H.sub.1, H.sub.2) are arranged so that the inlet of the second heating section (H.sub.2) is operatively associated with the outlet of the first heating section (H.sub.1). A moisture separator (126) having a vapor outlet (164) and a liquid outlet (144) is operatively associated with the outlet (124) of the second heating section (H.sub.2). A cooling section (C.sub.1) is operatively associated with the liquid outlet (144) of the moisture separator (126) and includes an outlet that is operatively associated with the inlet of the second heating section (H.sub.2).
Bharathan, Desikan (Lakewood, CO); Hassani, Vahab (Golden, CO)
This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.
Eric M. Suuberg; Vahur Oja
Method for deposition of a conductor in integrated circuits
A method is described for fabricating integrated semiconductor circuits and, more particularly, for the selective deposition of a conductor onto a substrate employing a chemical vapor deposition process. By way of example, tungsten can be selectively deposited onto a silicon substrate. At the onset of loss of selectivity of deposition of tungsten onto the silicon substrate, the deposition process is interrupted and unwanted tungsten which has deposited on a mask layer with the silicon substrate can be removed employing a halogen etchant. Thereafter, a plurality of deposition/etch back cycles can be carried out to achieve a predetermined thickness of tungsten.
Creighton, J. Randall (Albuquerque, NM); Dominguez, Frank (Albuquerque, NM); Johnson, A. Wayne (Albuquerque, NM); Omstead, Thomas R. (Albuquerque, NM)
Grain size dependent mechanical properties of nanocrystalline diamond films grown by hot-filament CVD
Nanocrystalline diamond (NCD) films with a thickness of {approx}6 {micro}m and with average grain sizes ranging from 60 to 9 nm were deposited on silicon wafers using a hot-filament chemical vapor deposition (HFCVD) process. These samples were then characterized with the goal to identify correlations between grain size, chemical composition and mechanical properties. The characterization reveals that our films are phase pure and exhibit a relatively smooth surface morphology. The levels of sp{sup 2}-bonded carbon and hydrogen impurities are low, and showed a systematic variation with the grain size. The hydrogen content increases with decreasing grain size, whereas the sp{sup 2} carbon content decreases with decreasing grain size. The material is weaker than single crystalline diamond, and both stiffness and hardness decrease with decreasing grain size. These trends suggest gradual changes of the nature of the grain boundaries, from graphitic in the case of the 60 nm grain size material to hydrogen terminated sp{sup 3} carbon for the 9 nm grain size material. The films exhibit low levels of internal stress and freestanding structures with a length of several centimeters could be fabricated without noticeable bending.
Wiora, M; Bruehne, K; Floeter, A; Gluche, P; Willey, T M; Kucheyev, S O; Van Buuren, A W; Hamza, A V; Biener, J; Fecht, H
Near-field Microwave Scanning Probe Imaging of Conductivity Inhomogeneities in CVD Graphene
We have performed near-field scanning microwave microscopy (SMM) of graphene grown by chemical vapor deposition. Due to the use of probe-sample capacitive coupling and a relatively high ac frequency of a few GHz, this scanning probe method allows mapping of local conductivity without a dedicated counter electrode, with a spatial resolution of about 50 nm. Here, the coupling was enabled by atomic layer deposition of alumina on top of graphene, which in turn enabled imaging both large-area films, as well as micron-sized islands, with a dynamic range covering a low sheet resistance of a metal film and a high resistance of highly disordered graphene. The structures of graphene grown on Ni films and Cu foils are explored, and the effects of growth conditions are elucidated. We present a simple general scheme for interpretation of the contrast in the SMM images of our graphene samples and other two-dimensional conductors, which is supported by extensive numerical finite-element modeling. We further demonstrate that combination of the SMM and numerical modeling allows quantitative information about the sheet resistance of graphene to be obtained, paving the pathway for characterization of graphene conductivity with a sub-100 nm special resolution.
Tselev, Alexander [ORNL; Lavrik, Nickolay V [ORNL; Vlassiouk, Ivan V [ORNL; Briggs, Dayrl P [ORNL; Rutgers, Maarten [Asylum Research, Santa Barbara, CA; Proksch, Roger [Asylum Research, Santa Barbara, CA; Kalinin, Sergei V [ORNL
Dynamic modeling of plasma-vapor interactions during plasma disruptions
Intense deposition of energy in short times on fusion reactor components during a plasma disruption may cause severe surface erosion due to ablation of these components. The exact amount of the eroded material is very important to the reactor design and its lifetime. During the plasma deposition, the vaporized wall material will interact with the incoming plasma particles and may shield the rest of the wall from damage. The vapor shielding may then prolong the lifetime of these components and increase the reactor duty cycle. To correctly evaluate the impact of vapor shielding effect a comprehensive model is developed. In this model the dynamic slowing down of the plasma particles, both ions and electrons, with the eroded wall material is established. Different interaction processes between the plasma particles and the ablated material is included. The generated photons radiation source and the transport of this radiation through the vapor to the wall is modeled. Recent experimental data on disruptions is analyzed and compared with model predictions. Vapor shielding may be effective in reducing the overall erosion rate for certain plasma disruption parameters and conditions.
Hassanein, A.; Ehst, D.A.
Argonne CNM News: STM of individual grains in CVD-grown graphene
STM of individual grains in CVD-grown graphene STM of individual grains in CVD-grown graphene SEM of 3d supercrystals The first scanning tunneling microscopy (STM) images of graphene synthesized on copper foil. (b-d) show atomic-resolution images at various locations of the large graphene domain shown in (a). NMAT June 2011 Users from Purdue University, working collaboratively with staff in the Electronic & Magnetic Materials & Devices Group, studied CVD-grown graphene on polycrystalline copper foil for the first time at the atomic-scale. The ultrahigh vacuum scanning tunneling microscopy (UHV-STM) findings performed at the Center for Nanoscale Materials (CNM) will help to guide the optimization of synthesis towards defect-free graphene. The focus of this study was to investigate the quality of the films and
Cold Vacuum Dryer (CVD) Facility Fire Protection System Design Description (SYS 24)
This system design description (SDD) addresses the Cold Vacuum Drying (CVD) Facility fire protection system (FPS). The primary features of the FPS for the CVD are a fire alarm and detection system, automatic sprinklers, and fire hydrants. The FPS also includes fire extinguishers located throughout the facility and fire hydrants to assist in manual firefighting efforts. In addition, a fire barrier separates the operations support (administrative) area from the process bays and process bay support areas. Administrative controls to limit combustible materials have been established and are a part of the overall fire protection program. The FPS is augmented by assistance from the Hanford Fire Department (HED) and by interface systems including service water, electrical power, drains, instrumentation and controls. This SDD, when used in conjunction with the other elements of the definitive design package, provides a complete picture of the FPS for the CVD Facility.
Variable temperature semiconductor film deposition
A method of depositing a semiconductor material on a substrate is disclosed. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.
Li, X.; Sheldon, P.
Vapor spill pipe monitor
The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.
Bianchini, G.M.; McRae, T.G.
Ultrashort pulse laser deposition of thin films
Short pulse PLD is a viable technique of producing high quality films with properties very close to that of crystalline diamond. The plasma generated using femtosecond lasers is composed of single atom ions with no clusters producing films with high Sp.sup.3 /Sp.sup.2 ratios. Using a high average power femtosecond laser system, the present invention dramatically increases deposition rates to up to 25 .mu.m/hr (which exceeds many CVD processes) while growing particulate-free films. In the present invention, deposition rates is a function of laser wavelength, laser fluence, laser spot size, and target/substrate separation. The relevant laser parameters are shown to ensure particulate-free growth, and characterizations of the films grown are made using several diagnostic techniques including electron energy loss spectroscopy (EELS) and Raman spectroscopy.
Perry, Michael D. (Livermore, CA); Banks, Paul S. (Livermore, CA); Stuart, Brent C. (Fremont, CA)
CuIn(1-x)Ga(x)Se-Based Solar Cells prepared from Electrodeposited and Electroless-Deposited Precursors
Three devices were fabricated from electrodeposited (ED) and electroless-deposited (EL) precursors. Compositions were adjusted with additional In and Ga by physical vapor deposition (PVD) for an ED and an EL device.
Batchelor, W. K.; Bhattacharya, R. N.
Ge integration on Si via rare earth oxide buffers: From MBE to CVD (Invited Paper)
Single crystalline rare earth oxide heterostructures are flexible buffer systems to achieve the monolithic integration of Ge thin film structures on Si. The development of engineered oxide systems suitable for mass-production compatible CVD processes ... Keywords: Engineered Si wafers, Ge integration, Heteroepitaxy, Rare earth oxides, X-ray diffraction
T. Schroeder; A. Giussani; H. -J. Muessig; G. Weidner; I. Costina; Ch. Wenger; M. Lukosius; P. Storck; P. Zaumseil
REVIEW ARTICLE Functional semiconductor nanowires via vapor deposition
in cell voltage could be obtained with more active catalysts. In the HBr electrolyzer, dramatic/cm2 at 1.91V. The SO2 process reached 0.4 A/cm2, but behind this current density the cell experienced hydrogen; Thermochemical 1. Introduction Recent advances in fuel cell technology and an increasing demand
Wang, Xudong
Micro Chemical Vapor Deposition for the Synthesis of Nanomaterials
delivery," Current Opinion in Chemical Biology, vol. 9, pp.Journal of the American Chemical Society, vol. 126, pp.Park and R. S. Ruoff, "Chemical methods for the production
Zhou, Qin
NREL: Awards and Honors - High-Rate Vapor Transport Deposition...
modules. In its first year of production, the technology has helped First Solar cut the price of PV modules to 2.50 per watt. The potential is even greater. A second-generation...
distribution when the heat conduction through 1-?m-thick gasdistribution when heat conduction through the 1-?m-thick gaslarge area and the heat conduction through the gases is
Graphene growth with giant domains using chemical vapor deposition
N. Martensson, Controlling graphene corrugation on lattice-in patterned epitaxial graphene, Science, 2006, 312(5777), 92009, 4(6), 17 A. K. Geim, Graphene: Status and Prospects,
Yong, Virginia; Hahn, H. Thomas
Plasma enhanced chemical vapor deposition vanadium oxide thin ...
... exhibits a high discharge capacity, a high energy density, and a negligible capacity fade fiom its second cycle to at least 2,900 cycles, ...
An apparatus for fabricating thin film materials utilizing high speed gas dynamics relies on supersonic free jets of carrier gas to transport depositing vapor species generated in a microwave discharge to the surface of a prepared substrate where the vapor deposits to form a thin film. The present invention generates high rates of deposition and thin films of unforeseen high quality at low temperatures. 5 figures.
Schmitt, J.J. III; Halpern, B.L.
Molybdenum enhanced low-temperature deposition of crystalline silicon nitride
A process for chemical vapor deposition of crystalline silicon nitride which comprises the steps of: introducing a mixture of a silicon source, a molybdenum source, a nitrogen source, and a hydrogen source into a vessel containing a suitable substrate; and thermally decomposing the mixture to deposit onto the substrate a coating comprising crystalline silicon nitride containing a dispersion of molybdenum silicide.
Lowden, Richard A. (Powell, TN)
J. Aerosol Sci. Vol. 29, Suppl. 1. pp. S79-S80. 1998 0 1998 Published by Elsevier Science Ltd. All rights reserved
Engineering, Minneapolis, MN 55455 USA KEYWORDS Nucleation, Silicon CVD, Silane, Chemical Kinetics Product that can be obtained during chemical vapor deposition (CVD) of materials for microelectronics applications-Induced Fluorescence Measurements and Kinetic Analysis of Si Atom Formation in a Rotating Disk Chemical Vapor
Swihart, Mark T.
Crystal Silicon Heterojunction Solar Cells by Hot-Wire CVD: Preprint
Hot-wire chemical vapor deposition (HWCVD) is a promising technique for fabricating Silicon heterojunction (SHJ) solar cells. In this paper we describe our efforts to increase the open circuit voltage (Voc) while improving the efficiency of these devices. On p-type c-Si float-zone wafers, we used a double heterojunction structure with an amorphous n/i contact to the top surface and an i/p contact to the back surface to obtain an open circuit voltage (Voc) of 679 mV in a 0.9 cm2 cell with an independently confirmed efficiency of 19.1%. This is the best reported performance for a cell of this configuration. We also made progress on p-type CZ wafers and achieved 18.7% independently confirmed efficiency with little degradation under prolong illumination. Our best Voc for a p-type SHJ cell is 0.688 V, which is close to the 691 mV we achieved for SHJ cells on n type c-Si wafers.
Wang, Q.; Page, M. R.; Iwaniczko, E.; Xu, Y. Q.; Roybal, L.; Bauer, R.; To, B.; Yuan, H. C.; Duda, A.; Yan, Y. F.
Vapor etching of nuclear tracks in dielectric materials
A process involving vapor etching of nuclear tracks in dielectric materials for creating high aspect ratio (i.e., length much greater than diameter), isolated cylindrical holes in dielectric materials that have been exposed to high-energy atomic particles. The process includes cleaning the surface of the tracked material and exposing the cleaned surface to a vapor of a suitable etchant. Independent control of the temperatures of the vapor and the tracked materials provide the means to vary separately the etch rates for the latent track region and the non-tracked material. As a rule, the tracked regions etch at a greater rate than the non-tracked regions. In addition, the vapor-etched holes can be enlarged and smoothed by subsequent dipping in a liquid etchant. The 20-1000 nm diameter holes resulting from the vapor etching process can be useful as molds for electroplating nanometer-sized filaments, etching gate cavities for deposition of nano-cones, developing high-aspect ratio holes in trackable resists, and as filters for a variety of molecular-sized particles in virtually any liquid or gas by selecting the dielectric material that is compatible with the liquid or gas of interest.
Musket, Ronald G. (Danville, CA); Porter, John D. (Berkeley, CA); Yoshiyama, James M. (Fremont, CA); Contolini, Robert J. (Lake Oswego, OR)
Drying of pulverized material with heated condensible vapor
Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fines, on the outer lateral surface thereof. The cooled collection fines are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized materials then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal. 2 figs.
Carlson, L.W.
Atmospheric Pressure Plasma CVD of Amorphous Hydrogenated Silicon Carbonitride (a-SiCN:H) Films Using Triethylsilane and Nitrogen
Amorphous hydrogenated silicon carbonitride (a-SiCN:H) thin films are synthesized by atmospheric pressure plasma enhanced chemical vapor (AP-PECVD) deposition using the Surfx Atomflow{trademark} 250D APPJ source with triethylsilane (HSiEt{sub 3}, TES) and nitrogen as the precursor and the reactive gases, respectively. The effect of the substrate temperature (T{sub s}) on the growth characteristics and the properties of a-SiCN:H films was evaluated. The properties of the films were investigated via scanning electron microscopy (SEM), atomic force microscopy (AFM) for surface morphological analyses, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) for chemical and compositional analyses; spectroscopic ellipsometry for optical properties and thickness determination and nanoindentation to determine the mechanical properties of the a-SiCN:H films. Films deposited at low T{sub s} depict organic like features, while the films deposited at high T{sub s} depict ceramic like features. FTIR and XPS studies reveal that an increases in T{sub s} helps in the elimination of organic moieties and incorporation of nitrogen in the film. Films deposited at T{sub s} of 425 C have an index of refraction (n) of 1.84 and hardness (H) of 14.8 GPa. A decrease in the deposition rate between T{sub s} of 25 and 250 C and increase in deposition rate between T{sub s} of 250 and 425 C indicate that the growth of a-SiCN:H films at lower T{sub s} are surface reaction controlled, while at high temperatures film growth is mass-transport controlled. Based on the experimental results, a potential route for film growth is proposed.
Srinivasan Guruvenket; Steven Andrie; Mark Simon; Kyle W. Johnson; Robert A. Sailer
This patent relates to a water-cooled vapor shield for an inductlon furnace that will condense metallic vapors arising from the crucible and thus prevent their condensation on or near the induction coils, thereby eliminating possible corrosion or shorting out of the coils. This is accomplished by placing, about the top, of the crucible a disk, apron, and cooling jacket that separates the area of the coils from the interior of the cruclbIe and provides a cooled surface upon whlch the vapors may condense.
Reese, S.L.; Samoriga, S.A.
Vapor adsorption process
The removal of undesirable acid components from sour natural gas is often accomplished by a vapor adsorption process wherein a bed of solid adsorbent material is contacted with an inlet gas stream so that desired components contained in the gas stream are adsorbed on the bed, then regenerated by contact with a heated regeneration gas stream. Adsorbed components are desorbed from the bed and the bed is cooled preparatory to again being contacted with the inlet gas stream. By this process, the bed is contacted, during the regeneration cycle, with a selected adsorbable material. This material has the property of being displaced from the bed by the desired components and has a heat of desorption equal to or greater than the heat of adsorption of the desired components. When the bed is contacted with the inlet gas stream, the selected adsorbable material is displaced by the desired components resulting in the temperature of the bed remaining relatively constant, thereby allowing the utilization of the maximum bed adsorption capacity. (4 claims)
Snyder, C.F.; Casad, B.M.
Atmospheric Water Vapor over China
Chinese radiosonde data from 1970 to 1990 are relatively homogeneous in time and are used to examine the climatology, trends, and variability of China�s atmospheric water vapor content. The climatological distribution of precipitable water (PW) ...
Panmao Zhai; Robert E. Eskridge
In situ analysis of ash deposits from black liquor combustion
Aerosols formed during combustion of black liquor cause a significant fire-side fouling problem in pulp mill recovery boilers. The ash deposits reduce heat transfer effectiveness, plug gas passages, and contribute to corrosion. Both vapors and condensation aerosols lead to the formation of such deposits. The high ash content of the fuel and the low dew point of the condensate salts lead to a high aerosol and vapor concentration in most boilers. In situ measurements of the chemical composition of these deposits is an important step in gaining a fundamental understanding of the deposition process. Infrared emission spectroscopy is used to characterize the composition of thin film deposits resulting from the combustion of black liquor and the deposition of submicron aerosols and vapors. New reference spectra of Na{sub 2}SO{sub 4}, K{sub 2}SO{sub 4}, Na{sub 2}CO{sub 3} and K{sub 2}CO{sub 3} pure component films were recorded and compared with the spectra of the black liquor deposit. All of the black liquor emission bands were identified using a combination of literature data and ab initio calculations. Ab initio calculations also predict the locations and intensities of bands for the alkali vapors of interest. 39 refs., 9 figs.
Bernath, P. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility]|[Univ. of Toronto, Ontario (Canada); Sinquefield, S.A. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility]|[Oregon State Univ., Eugene, OR (United States); Baxter, L.L.; Sclippa, G.; Rohlfing, C. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Barfield, M. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility]|[Univ. of Arizona, Tucson, AZ (United States)
Impact of TiN post-treatment on metal insulator metal capacitor performances
When deposited by chemical vapor deposition (CVD), TiN layers must be post-treated with N"2/H"2 plasma. Metal-insulator-metal (MIM) capacitors using CVD-TiN as electrodes and Al"2O"3 as insulator are studied from both electrical and physico-chemical ... Keywords: EELS analysis, Electrical characteristics, MIM capacitors, TiN post-treatment
A. Bajolet; J-P. Manceau; S. Bruy�re; R. Clerc; M. Proust; N. Gaillard; J-C. Giraudin; P. Delpech; L. Mont�s; G. Ghibaudo
Method of depositing a catalyst on a fuel cell electrode
Fuel cell electrodes comprising a minimal load of catalyst having maximum catalytic activity and a method of forming such fuel cell electrodes. The method comprises vaporizing a catalyst, preferably platinum, in a vacuum to form a catalyst vapor. A catalytically effective amount of the catalyst vapor is deposited onto a carbon catalyst support on the fuel cell electrode. The electrode preferably is carbon cloth. The method reduces the amount of catalyst needed for a high performance fuel cell electrode to about 0.3 mg/cm.sup.2 or less.
Dearnaley, Geoffrey (San Antonio, TX); Arps, James H. (San Antonio, TX)
Image Storage in Hot Vapors
We theoretically investigate image propagation and storage in hot atomic vapor. A $4f$ system is adopted for imaging and an atomic vapor cell is placed over the transform plane. The Fraunhofer diffraction pattern of an object in the object plane can thus be transformed into atomic Raman coherence according to the idea of ``light storage''. We investigate how the stored diffraction pattern evolves under diffusion. Our result indicates, under appropriate conditions, that an image can be reconstructed with high fidelity. The main reason for this procedure to work is the fact that diffusion of opposite-phase components of the diffraction pattern interfere destructively.
Zhao, L; Xiao, Y; Yelin, S F
L. Zhao; T. Wang; Y. Xiao; S. F. Yelin
Deposition Process
Pulsed Plasma Processing Pulsed Plasma Processing NEW: Downloadable: Invited Talk "Pulsed Metal Plasmas," presented at the 2006 AVS Meeting, San Francisco, California, November 15, 2006. (PDF, file size 8 MB). Plasma Sources for Window Coatings Deposition processes for low-emittance and solar control coatings can be improved through the use of advanced plasma technology developed at LBNL. A new type of constricted glow-discharge plasma source was selected for the 1997 R&D 100 Award. Invented by LBNL researchers Andre Anders, Mike Rubin, and Mike Dickinson, the source was designed to be compatible with industrial vacuum deposition equipment and practice. Construction is simple, rugged and inexpensive. It can operate indefinitely over a wide range of chamber pressure without any consumable parts such as filaments or grids. Several different gases including Argon, Oxygen and Nitrogen have been tested successfully.
Laboratory and In Situ Observation of Deposition Growth of Frozen Drops
The water vapor deposition growth of frozen drops with diameter greater than 100 ?m has been studied in a thermal diffusion chamber. For varying periods of time, it was found that frozen drops experience spherical growth. The characteristic time ...
Alexei V. Korolev; Matthew P. Bailey; John Hallett; George A. Isaac
Application of Vacuum Deposition Methods to Solid Oxide Fuel Cells
The application of vacuum deposition techniques to the fabrication of solid oxide fuel cell materials and structures are reviewed, focusing on magnetron sputtering, vacuum plasma methods, laser ablation, and electrochemical vapor deposition. A description of each method and examples of use to produce electrolyte, electrode, and/or electrical interconnects are given. Generally high equipment costs and relatively low deposition rates have limited the use of vacuum deposition methods in solid oxide fuel cell manufacture, with a few notable exceptions. Vacuum methods are particularly promising in the fabrication of micro fuel cells, where thin films of high quality and unusual configuration are desired.
Pederson, Larry R.; Singh, Prabhakar; Zhou, Xiao Dong
Atomic vapor laser isotope separation process
A laser spectroscopy system is utilized in an atomic vapor laser isotope separation process. The system determines spectral components of an atomic vapor utilizing a laser heterodyne technique. 23 figs.
Wyeth, R.W.; Paisner, J.A.; Story, T.
Vapor Pressure Measurement of Supercooled Water
A new dewpoint hygrometer was developed for subfreezing temperature application. Vapor pressure of supercooled water was determined by measuring temperatures at the dew-forming surface and the vapor source ice under the flux density balance, and ...
N. Fukuta; C. M. Gramada
Distribution of Tropical Tropospheric Water Vapor
Utilizing a conceptual model for tropical convection and observational data for water vapor, the maintenance of the vertical distribution of the tropical tropospheric water vapor is discussed. While deep convection induces large-scale subsidence ...
De-Zheng Sun; Richard S. Lindzen
Atmospheric Water Vapor Characteristics at 70�N
Using an extensive rawinsonde archive, characteristics of Arctic water vapor and its transports at 70�N are examined for the period 1974�1991. Monthly-mean profiles and vertically integrated values of specific humidity and meridional vapor fluxes ...
Mark C. Serreze; Roger G. Barry; John E. Walsh
Vapor phase modifiers for oxidative coupling
Volatilized metal compounds retard vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.
Warren, Barbara K. (Charleston, WV)
Chemical deposition methods using supercritical fluid solutions
A method for depositing a film of a desired material on a substrate comprises dissolving at least one reagent in a supercritical fluid comprising at least one solvent. Either the reagent is capable of reacting with or is a precursor of a compound capable of reacting with the solvent to form the desired product, or at least one additional reagent is included in the supercritical solution and is capable of reacting with or is a precursor of a compound capable of reacting with the first reagent or with a compound derived from the first reagent to form the desired material. The supercritical solution is expanded to produce a vapor or aerosol and a chemical reaction is induced in the vapor or aerosol so that a film of the desired material resulting from the chemical reaction is deposited on the substrate surface. In an alternate embodiment, the supercritical solution containing at least one reagent is expanded to produce a vapor or aerosol which is then mixed with a gas containing at least one additional reagent. A chemical reaction is induced in the resulting mixture so that a film of the desired material is deposited.
Sievers, Robert E. (Boulder, CO); Hansen, Brian N. (Boulder, CO)
Vapor Pressures and Heats of Vaporization of Primary Coal Tars
Office of Scientific and Technical Information (OSTI)
/ PC92544-18 / PC92544-18 VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS FINAL REPORT Grant Dates: August, 1992 - November, 1996 Principal Authors: Eric M. Suuberg (PI) and Vahur Oja Report Submitted: April, 1997 Revised: July, 1997 Grant Number: DE-FG22-92PC92544 Report Submitted by: ERIC M. SUUBERG DIVISION OF ENGINEERING BROWN UNIVERSITY PROVIDENCE, RI 02912 TEL. (401) 863-1420 Prepared For: U. S. DEPT. OF ENERGY FEDERAL ENERGY TECHNOLOGY CENTER P.O. BOX 10940 PITTSBURGH, PA 15236 DR. KAMALENDU DAS, FETC, MORGANTOWN , WV TECHNICAL PROJECT OFFICER "US/DOE Patent Clearance is not required prior to the publication of this document" ii United States Government Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any
GaN CVD Reactions: Hydrogen and Ammonia Decomposition and the Desorption of Gallium
Isotopic labeling experiments have revealed correlations between hydrogen reactions, Ga desorption, and ammonia decomposition in GaN CVD. Low energy electron diffraction (LEED) and temperature programmed desorption (TPD) were used to demonstrate that hydrogen atoms are available on the surface for reaction after exposing GaN(0001) to deuterium at elevated temperatures. Hydrogen reactions also lowered the temperature for Ga desorption significantly. Ammonia did not decompose on the surface before hydrogen exposure. However, after hydrogen reactions altered the surface, N15H3 did undergo both reversible and irreversible decomposition. This also resulted in the desorption of N2 of mixed isotopes below the onset of GaN sublimation, This suggests that the driving force of the high nitrogen-nitrogen bond strength (226 kcal/mol) can lead to the removal of nitrogen from the substrate when the surface is nitrogen rich. Overall, these findings indicate that hydrogen can influence G-aN CVD significantly, being a common factor in the reactivity of the surface, the desorption of Ga, and the decomposition of ammonia.
Bartram, Michael E.; Creighton, J. Randall
A process for chemical vapor deposition of crystalline silicon nitride is described which comprises the steps of: introducing a mixture of a silicon source, a molybdenum source, a nitrogen source, and a hydrogen source into a vessel containing a suitable substrate; and thermally decomposing the mixture to deposit onto the substrate a coating comprising crystalline silicon nitride containing a dispersion of molybdenum silicide. 5 figures.
Lowden, R.A.
Means and method for vapor generation
A liquid, in heat transfer contact with a surface heated to a temperature well above the vaporization temperature of the liquid, will undergo a multiphase (liquid-vapor) transformation from 0% vapor to 100% vapor. During this transition, the temperature driving force or heat flux and the coefficients of heat transfer across the fluid-solid interface, and the vapor percentage influence the type of heating of the fluid--starting as "feedwater" heating where no vapors are present, progressing to "nucleate" heating where vaporization begins and some vapors are present, and concluding with "film" heating where only vapors are present. Unstable heating between nucleate and film heating can occur, accompanied by possibly large and rapid temperature shifts in the structures. This invention provides for injecting into the region of potential unstable heating and proximate the heated surface superheated vapors in sufficient quantities operable to rapidly increase the vapor percentage of the multiphase mixture by perhaps 10-30% and thereby effectively shift the multiphase mixture beyond the unstable heating region and up to the stable film heating region.
Carlson, Larry W. (Oswego, IL)
Evaporation system and method for gas jet deposition of thin film materials
A method and apparatus for depositing thin films of materials such as metals, oxides and nitrides at low temperature relies on a supersonic free jet of inert carrier gas to transport vapor species generated from an evaporation source to the surface of a substrate. Film deposition vapors are generated from solid film precursor materials, including those in the form of wires or powders. The vapor from these sources is carried downstream in a low pressure supersonic jet of inert gas to the surface of a substrate where the vapors deposit to form a thin film. A reactant gas can be introduced into the gas jet to form a reaction product with the evaporated material. The substrate can be moved from the gas jet past a gas jet containing a reactant gas in which a discharge has been generated, the speed of movement being sufficient to form a thin film which is chemically composed of the evaporated material and reactant gases.
Schmitt, Jerome J. (New Haven, CT); Halpern, Bret L. (Bethany, CT)
Spent Nuclear Fuel (SNF) Cold Vacuum Drying (CVD) Facility Operations Manual
This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-553, Spent Nuclear Fuel Project Final Safety Analysis Report Annex B--Cold Vacuum Drying Facility. The HNF-SD-SNF-DRD-002, 1999, Cold Vacuum Drying Facility Design Requirements, Rev. 4, and the CVDF Final Design Report. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence and references to the CVDF System Design Descriptions (SDDs). This manual has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved.
Design and Application of CVD Diamond Windows for X-Rays at the Advanced Photon Source
Two types of directly cooled, 0.2-mm-thick, 8-mm-diameter clear aperture CVD diamond windows have been designed and successfully fabricated by two different vendors for use at the Advanced Photon Source (APS). Both windows contain a direct braze joint between the diamond and the cooled OFHC copper. These windows can be used to replace the front-end beryllium windows in high-heat-load applications and can be used as white beam windows in the beamlines. This paper presents the detailed design of the diamond windows, the thermal analysis of the diamond window under different thermal load configurations, as well as a complete list of the existing APS front-end beryllium window configurations and replacement scenarios. Small-angle scattering experiments have been conducted on both diamond windows and a polished beryllium window, and the results are presented.
Jaski, Yifei [Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave, Bldg 401, Argonne, IL 60439 (United States); Cookson, David [University of Chicago, CARS, APS Sector 15, 9700 S. Cass Ave, Bldg. 434D, Argonne, IL 60439 (United States)
Design and application of CVD diamond windows for x-rays at the Advanced Photon Source.
Jaski, Y.; Cookson, D.; Experimental Facilities Division (APS); Univ. of Chicago
Spent Nuclear Fuel (SNF) Project Cold Vacuum Drying (CVD) Facility Operations Manual
This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of the Processing Systems (Garvin 1998) and, the HNF-SD-SNF-DRD-002, 1997, Cold Vacuum Drying Facility Design Requirements, Rev. 3a. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence, and has been developed for the spent nuclear fuel project (SNFP) Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved.
Vapor phase heat transport systems
Vapor phase heat-transport systems are being tested in two of the passive test cells at Los Alamos. The systems consist of an active fin-and-tube solar collector and a condenser inside a water storage tank. The refrigerant, R-11, can be returned to the collector by a pump or by a self-pumping scheme. In one of the test cells the liquid was self-pumped to the roof-mounted collector 17 ft above the condenser. A mechanical valve was designed and tested that showed that the system could operate in a completely passive mode. Performance comparisons have been made with a passive water wall test cell.
Hedstrom, J.C.
An apparatus and a method are described for continuous vacuum deposition of metals for metallic coatings, for ultra-high vacuum work, for purification of metals, for maintaining high-density electron currents, and for other uses. The apparatus comprises an externally cooled feeder tube extending into a container and adapted to feed metal wire or strip so that it emerges in a generally vertical position therein. The tube also provides shielding from the heat produced by an electron beam therein focused to impinge from a vertical direction upon the tip of the emerging wire. By proper control of the wire feed, coolant feed, and electron beam intensity, a molten ball of metal forms upon the emerging tip and remains self-supported thereon by the interaction of various forces. The metal is vaporized and travels in a line of sight direction, while additional wire is fed from the tube, so that the size of the molten ball remains constant. In the preferred embodiments, the wire is selected from a number of gettering metals and is degassed by electrical resistance in an adjacent chamber which is also partially evacuated. The wire is then fed through the feed tube into the electron beam and vaporizes and adsorbs gases to provide pumping action while being continuously deposited upon surfaces within the chamber. Ion pump electrodes may also be provided within line of sight of the vaporizing metal source to enhance the pumping action. (AEC)
Milleron, N.
Coupling apparatus for a metal vapor laser
Coupling apparatus for a large bore metal vapor laser is disclosed. The coupling apparatus provides for coupling high voltage pulses (approximately 40 KV) to a metal vapor laser with a high repetition rate (approximately 5 KHz). The coupling apparatus utilizes existing thyratron circuits and provides suitable power input to a large bore metal vapor laser while maintaining satisfactory operating lifetimes for the existing thyratron circuits.
Ball, D.G.; Miller, J.L.
Mercury Vapor (Kooten, 1987) | Open Energy Information
Mercury Vapor (Kooten, 1987) Mercury Vapor (Kooten, 1987) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor (Kooten, 1987) Exploration Activity Details Location Unspecified Exploration Technique Mercury Vapor Activity Date Usefulness useful DOE-funding Unknown Notes Surface soil-mercury surveys are an inexpensive and useful exploration tool for geothermal resources. ---- Surface geochemical surveys for mercury were conducted in 16 areas in 1979-1981 by ARCO Oil and Gas Company as part of its geothermal evaluation program. Three techniques used together have proved satisfactory in evaluating surface mercury data. These are contouring, histograms and cumulative frequency plots of the data. Contouring geochemical data and constructing histograms are standard
Thermoplastic Composite with Vapor Grown Carbon Fiber.
??Vapor grown carbon fiber (VGCF) is a new class of highly graphitic carbon nanofiber and offers advantages of economy and simpler processing over continuous-fiber composites.� (more)
Lee, Jaewoo
Moisture Durability of Vapor Permeable Insulating Sheathing ...
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Existing Homes, Building Technologies Office (BTO) In this project, Building America team Building Science Corporation researched some of the ramifications of using exterior, vapor...
Volatilized metal compounds are described which are capable of retarding vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.
Warren, B.K.
Hybrid deposition of thin film solid oxide fuel cells and electrolyzers
The use of vapor deposition techniques enables synthesis of the basic components of a solid oxide fuel cell (SOFC); namely, the electrolyte layer, the two electrodes, and the electrolyte-electrode interfaces. Such vapor deposition techniques provide solutions to each of the three critical steps of material synthesis to produce a thin film solid oxide fuel cell (TFSOFC). The electrolyte is formed by reactive deposition of essentially any ion conducting oxide, such as defect free, yttria stabilized zirconia (YSZ) by planar magnetron sputtering. The electrodes are formed from ceramic powders sputter coated with an appropriate metal and sintered to a porous compact. The electrolyte-electrode interface is formed by chemical vapor deposition of zirconia compounds onto the porous electrodes to provide a dense, smooth surface on which to continue the growth of the defect-free electrolyte, whereby a single fuel cell or multiple cells may be fabricated. 8 figs.
Jankowski, A.F.; Makowiecki, D.M.; Rambach, G.D.; Randich, E.
The use of vapor deposition techniques enables synthesis of the basic components of a solid oxide fuel cell (SOFC); namely, the electrolyte layer, the two electrodes, and the electrolyte-electrode interfaces. Such vapor deposition techniques provide solutions to each of the three critical steps of material synthesis to produce a thin film solid oxide fuel cell (TFSOFC). The electrolyte is formed by reactive deposition of essentially any ion conducting oxide, such as defect free, yttria stabilized zirconia (YSZ) by planar magnetron sputtering. The electrodes are formed from ceramic powders sputter coated with an appropriate metal and sintered to a porous compact. The electrolyte-electrode interface is formed by chemical vapor deposition of zirconia compounds onto the porous electrodes to provide a dense, smooth surface on which to continue the growth of the defect-free electrolyte, whereby a single fuel cell or multiple cells may be fabricated.
Jankowski, Alan F. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA); Rambach, Glenn D. (Livermore, CA); Randich, Erik (Endinboro, PA)
Water Vapor Fields Deduced from METEOSAT-1 Water Vapor Channel Data
A quasi-operational process for the determination of water vapor fields from METEPSAT-1 water vapor channel data is described. Each count of the WV picture is replaced by the corresponding mean relative humidity value using both the calibration ...
M. M. Poc; M. Roulleau
Amorphous silicon technology
The growth methods discussed in this volume include both regular and remote plasma enhanced chemical vapor deposition (PECVD), catalytic CVD (CTLCVD), atmospheric pressure CVD (APCVD), very high frequency plasma CVD (VHCVD) and magnetron sputtering. Some of the papers discuss the use of disilane to increase growth rates. The general questions of the kinetics of film growth is an important topic of discussion in this volume. Several mechanisms for monitoring film growth and lasma diagnostics are also topics of discussion.
Madan, A. (Glasstech Solar, Inc., Wheatridge, CO (USA)); Thompson, M.J. (Xerox Palo Alto Research Center, CA (USA)); Taylor, P.C. (Univ. of Utah, Salt Lake City, UT (US)); LeComber, P.G. (Univ. of Dundee, Dundee (GB)); Hamakawa, Y. (Osaka Univ., Osaka (JP))
Nitrogen Deposition Data Available
Nitrogen Deposition Data Available This data set, prepared by Elizabeth Holland and colleagues, contains data for wet and dry nitrogen-species deposition for the United States and...
G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) Value-Added Product
The G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) value-added product (VAP) computes precipitable water vapor using neural network techniques from data measured by the GVR. The GVR reports time-series measurements of brightness temperatures for four channels located at 183.3 � 1, 3, 7, and 14 GHz.
Koontz, A; Cadeddu, M
Near real time vapor detection and enhancement using aerosol adsorption
A vapor sample detection method where the vapor sample contains vapor and ambient air and surrounding natural background particles. The vapor sample detection method includes the steps of generating a supply of aerosol that have a particular effective median particle size, mixing the aerosol with the vapor sample forming aerosol and adsorbed vapor suspended in an air stream, impacting the suspended aerosol and adsorbed vapor upon a reflecting element, alternatively directing infrared light to the impacted aerosol and adsorbed vapor, detecting and analyzing the alternatively directed infrared light in essentially real time using a spectrometer and a microcomputer and identifying the vapor sample.
Novick, Vincent J.; Johnson, Stanley A.
Atomic vapor laser isotope separation
Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements.
Stern, R.C.; Paisner, J.A.
A New Global Water Vapor Dataset
A comprehensive and accurate global water vapor dataset is critical to the adequate understanding of water vapor's role in the earth's climate system. To begin to satisfy this need, the authors have produced a blended dataset made up of global, 5-...
David L. Randel; Thomas J. Greenwald; Thomas H. Vonder Haar; Graeme L. Stephens; Mark A. Ringerud; Cynthia L. Combs
LNG fire and vapor control system technologies
This report provides a review of fire and vapor control practices used in the liquefied natural gas (LNG) industry. Specific objectives of this effort were to summarize the state-of-the-art of LNG fire and vapor control; define representative LNG facilities and their associated fire and vapor control systems; and develop an approach for a quantitative effectiveness evaluation of LNG fire and vapor control systems. In this report a brief summary of LNG physical properties is given. This is followed by a discussion of basic fire and vapor control design philosophy and detailed reviews of fire and vapor control practices. The operating characteristics and typical applications and application limitations of leak detectors, fire detectors, dikes, coatings, closed circuit television, communication systems, dry chemicals, water, high expansion foam, carbon dioxide and halogenated hydrocarbons are described. Summary descriptions of a representative LNG peakshaving facility and import terminal are included in this report together with typical fire and vapor control systems and their locations in these types of facilities. This state-of-the-art review identifies large differences in the application of fire and vapor control systems throughout the LNG industry.
Konzek, G.J.; Yasutake, K.M.; Franklin, A.L.
Quantitative organic vapor-particle sampler
A quantitative organic vapor-particle sampler for sampling semi-volatile organic gases and particulate components. A semi-volatile organic reversible gas sorbent macroreticular resin agglomerates of randomly packed microspheres with the continuous porous structure of particles ranging in size between 0.05-10 .mu.m for use in an integrated diffusion vapor-particle sampler.
Gundel, Lara (Berkeley, CA); Daisey, Joan M. (Walnut Creek, CA); Stevens, Robert K. (Cary, NC)
Stacked vapor fed amtec modules
The present invention pertains to a stacked AMTEC module. The invention includes a tubular member which has an interior. The member is comprised of a ion conductor that substantially conducts ions relative to electrons, preferably a beta"-alumina solid electrolyte, positioned about the interior. A porous electrode for conducting electrons and allowing sodium ions to pass therethrough, and wherein electrons and sodium ions recombine to form sodium is positioned about the beta"-alumina solid electrolyte. The electrode is operated at a temperature and a pressure that allows the recombined sodium to vaporize. Additionally, an outer current collector grid for distributing electrons throughout the porous electrode is positioned about and contacts the porous electrode. Also included in the invention is transporting means for transporting liquid sodium to the beta"-alumina solid electrolyte of the tubular member. A transition piece is positioned about the interior of the member and contacts the transporting means. The transition piece divides the member into a first cell and a second cell such that each first and second cell has a beta"-alumina solid electrolyte, a first and second porous electrode and a grid. The transition piece conducts electrons from the interior of the tubular member. There is supply means for supplying sodium to the transporting means. Preferably the supply means is a shell which surrounds the tubular member and is operated at a temperature such that the vaporized sodium condenses thereon. Returning means for returning the condensed sodium from the shell to the transporting means provides a continuous supply of liquid sodium to the transporting means. Also, there are first conducting means for conducting electric current from the transition piece which extends through the shell, and second conducting means for conducting electric current to the grid of the first cell which extends through the shell.
Sievers, Robert K. (North Huntingdon, PA)
ARM - Field Campaign - Water Vapor IOP
govCampaignsWater Vapor IOP govCampaignsWater Vapor IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Water Vapor IOP 2000.09.18 - 2000.10.08 Lead Scientist : Henry Revercomb Data Availability Yes For data sets, see below. Description Scientific hypothesis: 1. Microwave radiometer (MWR) observations of the 22 GHz water vapor line can accurately constrain the total column amount of water vapor (assuming a calibration accuracy of 0.5 degC or better, which translates into 0.35 mm PWV). 2. Continuous profiling by Raman lidar provides a stable reference for handling sampling problems and observes a fixed column directly above the site only requiring a single height- independent calibration factor. 3. Agreement between the salt-bath calibrated in-situ probes, chilled
Cold cathode vacuum discharge tube
A cold cathode vacuum discharge tube, and method for making same, with an interior surface of the trigger probe coated with carbon deposited by carbon vapor deposition (CVD) or diamond-like carbon (DLC) deposition. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging.
Boettcher, Gordon E. (Albuquerque, NM)
Metal oxide morphology in argon-assisted glancing angle deposition
Glancing angle deposition (GLAD) is a thin film deposition technique capable of fabricating columnar architectures such as posts, helices, and chevrons with control over nanoscale film features. Argon bombardment during deposition modifies the GLAD process, producing films with new morphologies which have shown promise for sensing and photonic devices. The authors report modification of column tilt angle, film density, and specific surface area for 12 different metal oxide and fluoride film materials deposited using Ar-assisted GLAD. For the vapor flux/ion beam geometry and materials studied here, with increasing argon flux, the column tilt increases, film density increases, and specific surface area decreases. With a better understanding of the nature of property modification and the mechanisms responsible, the Ar-assisted deposition process can be more effectively targeted towards specific applications, including birefringent thin films or photonic crystal square spirals.
Sorge, J. B.; Taschuk, M. T.; Wakefield, N. G.; Sit, J. C.; Brett, M. J. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 (Canada); Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 (Canada) and NRC National Institute for Nanotechnology, Edmonton, AB T6G 2M9 (Canada)
Cold Vacuum Drying (CVD) Facility General Service Helium System Design Description
The purpose of this System Design Description (SDD) is to describe the characteristics of the Cold Vacuum Drying (CVD) Facility general service helium system. The general service helium system is a general service facility process support system, but does include safety-class structures, systems and components (SSCs) providing protection to the offsite public. The general service helium system also performs safety-significant functions that provide protection to onsite workers. The general helium system essential function is to provide helium (He) to support process functions during all phases of facility operations. General service helium is used to purge the cask and the MCO in order to maintain their internal atmospheres below hydrogen flammability concentrations. The general service helium system also supplies helium to purge the process water conditioning (PWC) lines and components and the vacuum purge system (VPS) vacuum pump. The general service helium system, if available following an Safety Class Instrument and Control System (SCIC) Isolation and Purge (IS0 and PURGE) Trip, can provide an alternate general service helium system source to supply the Safety-Class Helium (SCHe) System.
Mercury Vapor At Desert Peak Area (Varekamp & Buseck, 1983) ...
Mercury Vapor At Desert Peak Area (Varekamp & Buseck, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor At Desert Peak Area...
Mercury Vapor At Socorro Mountain Area (Kooten, 1987) | Open...
Mercury Vapor At Socorro Mountain Area (Kooten, 1987) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor At Socorro Mountain Area...
Abstract: Apparatus for Measuring Vapor-Liquid Equilibrium ...
... Measurements of the vapor pressures and saturated liquid densities of ethanol and the vapor pressure of an ethanol water mixture (ethanol=0.6743 ...
Mercury Vapor At Mccoy Geothermal Area (DOE GTP) | Open Energy...
Mercury Vapor At Mccoy Geothermal Area (DOE GTP) Exploration Activity Details Location Mccoy Geothermal Area Exploration Technique Mercury Vapor Activity Date Usefulness not...
Water vapor retrieval over many surface types
In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.
Borel, C.C.; Clodius, W.C.; Johnson, J.
Modeling engine oil vaporization and transport of the oil vapor in the piston ring pack on internal combustion engines.
??A model was developed to study engine oil vaporization and oil vapor transport in the piston ring pack of internal combustion engines. With the assumption� (more)
Cho, Yeunwoo, 1973-
A kinetics study of the atmospheric pressure CVD reaction of silane and nitrous oxide
A mechanistic study of oxide deposition from silane and nitrous oxide between 495{sup 0}C and 690{sup 0}C was performed in a laminar flow, cool wall reactor. Results indicate the existence of two distinct chemical pathways. At high nitrous oxide concentrations, the deposition reaction is dominated by radical chain chemistry initiated by the decomposition of N/sub 2/O. At lower N/sub 2/O concentrations, the decomposition of silane to form silylene (SiH/sub 2/) initiates the deposition. Studies of the reaction of disilane and nitrous oxide confirmed the role of SiH/sub 2/ in the deposition. Reactions involving SiH/sub 2/ are used to explain the observed growth of sub-stoichiometric oxides under low N/sub 2/O conditions.
Chapple-Sokol, J.D.; Giunta, C.J.; Gordon, R.G. (Harvard Univ., Cambridge, MA (USA). Dept. of Chemistry)
Analysis of binary vapor turbines
The effect the binary mixture has on the turbine is examined in terms of design and cost. Several flow theories for turbines and turbine blading are reviewed. The similarity method, which uses dimensionless parameters, is used in determining rotative speeds and diameters for a variety of inlet temperatures and exit pressures. It is shown that the ratio of exit to inlet specific volume for each component in the mixture is the same for each specie. The specific volume ratio constraints are combined with the temperature equalities, the condenser pressure, and the total inlet entropy to form the constraints necessary to determine the exit state uniquely in an isentropic expansion. The non-isentropic exit state is found in a similar manner. The expansion process is examined for several cases and compared with the expansion of a single component vapor. Finally, in order to maintain high efficiency and to meet the criteria which makes the similarity method valid at high inlet temperatures, turbine multistaging is examined and a sample case is given for a two stage turbine.
Bliss, R.W.; Boehm, R.F.; Jacobs, H.R.
Etude cin\\'etique de CVD de pyrocarbone obtenu par pyrolyse de propane
High temeperature (900-1000\\degree C) low pressure (propane yields a pyrocarbon deposit, but also mainly hydrogen and hydrocarbons from methane to polyaromatics. 30 reaction products were exeperimentally quantified at different operating conditions. A detailed kinetic pyrolysis model (600 reactions) has been developed and validated based on the totality of experiments. This model includes a homogeneous model (describing the gas phase pyrolysis of propane) coupled with a heterogeneous model describing the pyrocarbon deposit.
Ziegler-Devin, Isabelle; Marquaire, Paul-Marie
chemical vapor deposition (PECVD) with a fixed germane to disilane ratio of 0.72 and a wide range], cathode deposition [2], and using disilane- germane mixture without H dilution [3] in PECVD process. A gas mixture of disilane, germane and hydrogen was used with a fixed germane to disilane ratio of 0
Published in J. Mat. Sci. Lettr. 18 (1999) 427-430 Selective Patterned Deposition of Diamond using a New Technique
of centrifugation on diamond deposition. It is generally believed that atomic hydrogen at the growth surface deposition were unsuitable for experiments on a centrifuge. Thus, a new closed chemical vapor transport and removal of gas [4]. Graphite was used as a carbon source in the presence of hydrogen at low pressure
Regel, Liya L.
Perfluorocarbon vapor tagging of blasting cap detonators
A plug for a blasting cap is made of an elastomer in which is dissolved a perfluorocarbon. The perfluorocarbon is released as a vapor into the ambient over a long period of time to serve as a detectable taggant.
Dietz, Russell N. (Shoreham, NY); Senum, Gunnar I. (Patchogue, NY)
Dietz, R.N.; Senum, G.I.
Tropospheric Water Vapor and Climate Sensitivity
Estimates are made of the effect of changes in tropospheric water vapor on the climate sensitivity to doubled carbon dioxide (CO2), using a coarse resolution atmospheric general circulation model coupled to a slab mixed layer ocean. The ...
Edwin K. Schneider; Ben P. Kirtman; Richard S. Lindzen
Multicomponent fuel vaporization at high pressures.
We extend our multicomponent fuel model to high pressures using a Peng-Robinson equation of state, and implement the model into KIVA-3V. Phase equilibrium is achieved by equating liquid and vapor fugacities. The latent heat of vaporization and fuel enthalpies are also corrected for at high pressures. Numerical simulations of multicomponent evaporation are performed for single droplets for a diesel fuel surrogate at different pressures.
Torres, D. J. (David J.); O'Rourke, P. J. (Peter J.)
Urania vapor composition at very high temperatures
Due to the chemically unstable nature of uranium dioxide its vapor composition at very high temperatures is, presently, not sufficiently studied though more experimental knowledge is needed for risk assessment of nuclear reactors. We used laser vaporization coupled to mass spectrometry of the produced vapor to study urania vapor composition at temperatures in the vicinity of its melting point and higher. The very good agreement between measured melting and freezing temperatures and between partial pressures measured on the temperature increase and decrease indicated that the change in stoichiometry during laser heating was very limited. The evolutions with temperature (in the range 2800-3400 K) of the partial pressures of the main vapor species (UO{sub 2}, UO{sub 3}, and UO{sub 2}{sup +}) were compared with theoretically predicted evolutions for equilibrium noncongruent gas-liquid and gas-solid phase coexistences and showed very good agreement. The measured main relative partial pressure ratios around 3300 K all agree with calculated values for total equilibrium between condensed and vapor phases. It is the first time the three main partial pressure ratios above stoichiometric liquid urania have been measured at the same temperature under conditions close to equilibrium noncongruent gas-liquid phase coexistence.
Pflieger, Rachel [Institute for Transuranium Elements, Joint Research Centre, European Commission, P.O. Box 2340, 76125 Karlsruhe (Germany); Marcoule Institute for Separation Chemistry (ICSM), UMR 5257, CEA-CNRS-UMII-ENSCM, Bagnols sur Ceze Cedex (France); Colle, Jean-Yves [Institute for Transuranium Elements, Joint Research Centre, European Commission, P.O. Box 2340, 76125 Karlsruhe (Germany); Iosilevskiy, Igor [Joint Institute for High Temperature, Russian Academy of Science, 125412 Moscow (Russian Federation); Moscow Institute of Physics and Technology, State University, 141700 Moscow (Russian Federation); Extreme Matter Institute (EMMI), 64291 Darmstadt (Germany); Sheindlin, Michael [Institute for Transuranium Elements, Joint Research Centre, European Commission, P.O. Box 2340, 76125 Karlsruhe (Germany); Joint Institute for High Temperature, Russian Academy of Science, 125412 Moscow (Russian Federation)
The impact of individualised cardiovascular disease (CVD) risk estimates and lifestyle advice on physical activity in individuals at high risk of CVD. A Pilot 2x2 Factorial "Understanding Risk" Trial.
. Medicine & Science in Sports & Exercise 1998, 30:777-781. 33. Ekelund U, �man J, Yngve A, Renman C, Westerterp K, Sj�str�m M: Physical activity but not energy expenditure is reduced in obese adolescents: a case-control study. American Journal of Clin- ical... and fatal CVD risk estimated using a modified version of the UKPDS Risk Engine[23]. This has an interface designed specifically for use in the study with the aim of achieving maximum comprehension by could achieve if they were to meet current targets[24...
Price, Hermione C; Tucker, Lynne; Griffin, Simon J; Holman, Rury R
Dry deposition of pan to grassland vegetation
Peroxyacetyl nitrate or PAN (CH{sub 3}C(O)OONO{sub 2}) is formed in the lower troposphere via photochemical reactions involving nitrogen oxides (NO{sub x}) and non-methane hydrocarbons (NMHCs). PAN has a lifetime in the free troposphere of about three months and is removed by photolysis or reaction with OH. Dry deposition will decrease its lifetime, although the few measurements that have been made indicate that this process is slow. Measurements of the uptake of PAN by alfalfa in growth chambers indicated that the dry deposition velocity (downward flux divided by concentration at a specified height) was 0.75 cm s{sup {minus}1}. Garland and Penkett measured a dry deposition velocity of 0.25 cm s{sup {minus}1} for PAN to grass and soil in a return-flow wind tunnel. Shepson et al. (1992) analyzed trends of PAN and O{sub 3} concentrations in the stable nocturnal boundary layer over mixed deciduous/coniferous forests at night, when leaf stomata were closed, and concluded that the deposition velocity for PAN was at least 0.5 cm s{sup {minus}1}. We measured the dry deposition velocity of PAN to a grassland site in the midwestern United States with a modified Bowen ratio technique. Experiments were conducted on selected days during September, October, and November of 1990. An energy balance Bowen ratio station was used to observe the differences in air temperature and water vapor content between heights of 3.0 and 0.92 m and to evaluate the surface energy balance. Air samples collected at the same two heights in Teflon {reg_sign} bags were analyzed for PAN by a gas chromatographic technique. We present an example of the variations of PAN concentrations and gradients observed during the day and compare measurements of the dry deposition velocity to expectations based on the physicochemical properties of PAN.
Doskey, P.V.; Wesely, M.L.; Cook, D.R.; Gao, W.
Vapor scavenging by atmospheric aerosol particles
Particle growth due to vapor scavenging was studied using both experimental and computational techniques. Vapor scavenging by particles is an important physical process in the atmosphere because it can result in changes to particle properties (e.g., size, shape, composition, and activity) and, thus, influence atmospheric phenomena in which particles play a role, such as cloud formation and long range transport. The influence of organic vapor on the evolution of a particle mass size distribution was investigated using a modified version of MAEROS (a multicomponent aerosol dynamics code). The modeling study attempted to identify the sources of organic aerosol observed by Novakov and Penner (1993) in a field study in Puerto Rico. Experimentally, vapor scavenging and particle growth were investigated using two techniques. The influence of the presence of organic vapor on the particle`s hydroscopicity was investigated using an electrodynamic balance. The charge on a particle was investigated theoretically and experimentally. A prototype apparatus--the refractive index thermal diffusion chamber (RITDC)--was developed to study multiple particles in the same environment at the same time.
Andrews, E.
govCampaignsWater Vapor IOP govCampaignsWater Vapor IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Water Vapor IOP 1996.09.10 - 1996.09.30 Lead Scientist : Henry Revercomb For data sets, see below. Summary SCHEDULE This IOP will be conducted from September 10 - 30, 1996 (coincident with the Fall ARM-UAV IOP). Instruments that do not require supervision will be operated continuously during this period. Instruments that do require supervision are presently planned to be operated for 8-hour periods each day. Because it is necessary to cover as broad a range of environmental conditions as possible, the daily 8-hour period will be shifted across the diurnal cycle as deemed appropriate during the IOP (but will be maintained as a contiguous 8-hour block).
atmospheric water vapor | OpenEI
atmospheric water vapor atmospheric water vapor Dataset Summary Description (Abstract): Monthly Average Solar Resource for 2-axis tracking concentrating collectors for Mexico, Central America, and the Caribbean Islands. (Purpose): Provide information on the solar resource potential for the data domain. The insolation values represent the average solar energy available to a concentrating collector, such as a dish collector, which tracks the sun continuously. Source NREL Date Released July 31st, 2006 (8 years ago) Date Updated October 30th, 2007 (7 years ago) Keywords atmospheric water vapor Carribean Islands Central America DNI GIS Mexico NREL GEF solar SWERA UNEP Data application/zip icon Download Shapefile (zip, 247.8 KiB) text/csv icon Download Data (csv, 370.6 KiB) Quality Metrics Level of Review Some Review
atmoshperic water vapor | OpenEI
atmoshperic water vapor atmoshperic water vapor Dataset Summary Description (Abstract): Monthly Average Solar Resource for flat-plate collectors tilted at latitude for China. Source NREL Date Released April 12th, 2005 (9 years ago) Date Updated October 30th, 2007 (7 years ago) Keywords atmoshperic water vapor China GEF GIS NREL solar SWERA TILT UNEP Data application/zip icon Download Shapefile (zip, 625.6 KiB) text/csv icon Download Data (csv, 704.1 KiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period 01/01/1985 - 12/31/1991 License License Open Data Commons Public Domain Dedication and Licence (PDDL) Comment Rate this dataset Usefulness of the metadata Average vote Your vote Usefulness of the dataset Average vote Your vote Ease of access
PROTECT YOUR BANKING INFORMATION: PROTECT YOUR BANKING INFORMATION: DO NOT complete this form until you are ready to submit it to the Payroll Department. DIRECT DEPOSIT REQUEST Directions: 1. Provide required information neatly, legibly; 2. If Checking Account Direct Deposit, include a voided check. a. DO NOT submit a deposit slip! 3. If Savings Account Direct Deposit, include a copy of savings card. 4. Sign this form; 5. Inter-office mail it to Craft Payroll at "P238." DIRECT DEPOSITION AUTHORIZATION I hereby authorize Los Alamos National Laboratory, hereinafter called The Laboratory, to initiate credit entries and, if necessary, debit entries and adjustments for any credit entries in error to my account listed on this form. If deposit is for:
Thermal electric vapor trap arrangement and method
A technique for trapping vapor within a section of a tube is disclosed herein. This technique utilizes a conventional, readily providable thermal electric device having a hot side and a cold side and means for powering the device to accomplish this. The cold side of this device is positioned sufficiently close to a predetermined section of the tube and is made sufficiently cold so that any condensable vapor passing through the predetermined tube section is condensed and trapped, preferably within the predetermined tube section itself.
Alger, Terry (Tracy, CA)
Adsorption of water vapor on reservoir rocks
Progress is reported on: adsorption of water vapor on reservoir rocks; theoretical investigation of adsorption; estimation of adsorption parameters from transient experiments; transient adsorption experiment -- salinity and noncondensible gas effects; the physics of injection of water into, transport and storage of fluids within, and production of vapor from geothermal reservoirs; injection optimization at the Geysers Geothermal Field; a model to test multiwell data interpretation for heterogeneous reservoirs; earth tide effects on downhole pressure measurements; and a finite-difference model for free surface gravity drainage well test analysis.
Development of a Beam Condition Monitor System for the Experimental Areas of the LHC Using CVD Diamond
The CERN Large Hadron Collider (LHC) will store 2808 bunches per colliding beam, each bunch consisting of 10^11 protons at an energy of 7 TeV. If there is a failure in an element of the accelerator, the resulting beam losses could cause damages not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor fast increments of particle fluxes near the interaction point and, if necessary, to generate an abort signal to the LHC accelerator control to dump the beams. The system is being developed initially for the CMS experiment but is sufficiently general to find potential applications elsewhere. Due to its high radiation hardness, CVD diamond has been studied for use as the BCM sensor. Various samples of CVD diamond have been characterized extensively with a Sr-90 source and high intensity test beams in order to assess the capabilities of such sensors and to study whether this detector technology is suitable for a BCM system. The results from these investigations are p...
Fern�ndez-Hernando, L
Method and Apparatus for Concentrating Vapors for Analysis
An apparatus and method are disclosed for pre-concentrating gaseous vapors for analysis. The invention finds application in conjunction with, e.g., analytical instruments where low detection limits for gaseous vapors are desirable. Vapors sorbed and concentrated within the bed of the apparatus can be thermally desorbed achieving at least partial separation of vapor mixtures. The apparatus is suitable, e.g., for preconcentration and sample injection, and provides greater resolution of peaks for vapors within vapor mixtures, yielding detection levels that are 10-10,000 times better than for direct sampling and analysis systems. Features are particularly useful for continuous unattended monitoring applications.
Grate, Jay W. (West Richland, WA); Baldwin, David L. (Kennewick, WA); Anheier, Jr., Norman C. (Richland, WA)
Polynomial Fits to Saturation Vapor Pressure
The authors describe eighth- and sixth-order polynomial fits to Wexler's and Hyland-Wexler's saturation-vapor-pressure expressions. Fits are provided in both least-squares and relative-error norms. Error analysis is presented. The authors show ...
Piotr J. Flatau; Robert L. Walko; William R. Cotton
Vaporization of synthetic fuels. Final report. [Thesis
The problem of transient droplet vaporization in a hot convective environment is examined. The main objective of the present study is to develop an algorithm for the droplet vaporization which is simple enough to be feasibly incorporated into a complete spray combustion analysis and yet will also account for the important physics such as liquid-phase internal circulation, unsteady droplet heating and axisymmetric gas-phase convection. A simplified liquid-phase model has been obtained based on the assumption of the existence of a Hill's spherical vortex inside the droplet together with some approximations made in the governing diffusion equation. The use of the simplified model in a spray situation has also been examined. It has been found that droplet heating and vaporization are essentially unsteady and droplet temperature is nonuniform for a significant portion of its lifetime. It has also been found that the droplet vaporization characteristic can be quite sensitive to the particular liquid-phase and gas-phase models. The results of the various models are compared with the existing experimental data. Due to large scattering in the experimental measurements, particularly the droplet diameter, no definite conclusion can be drawn based on the experimental data. Finally, certain research problems which are related to the present study are suggested for future studies.
Sirignano, W.A.; Yao, S.C.; Tong, A.Y.; Talley, D.
A Water Vapor Index from Satellite Measurements
A method for deriving a water vapor index is presented. An important feature of the index is the fact that it does not rely on radiosondes. Thus, it is not influenced by problems associated with radiosondes and the extent to which the horizontal ...
Larry M. McMillin; David S. Crosby; Mitchell D. Goldberg
Profiling Atmospheric Water Vapor by Microwave Radiometry
High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended Kaiman-Bucy filter ...
J. R. Wang; J. L. King; T. T. Wilheit; G. Szejwach; L. H. Gesell; R. A. Nieman; D. S. Niver; B. M. Krupp; J. A. Gagliano
Method of deposition of silicon carbide layers on substrates and product
A method for direct chemical vapor deposition of silicon carbide to substrates, especially nuclear waste particles, is provided by the thermal decomposition of methylsilane at about 800.degree. C. to 1050.degree. C. when the substrates have been confined within a suitable coating environment.
Angelini, Peter (Oak Ridge, TN); DeVore, Charles E. (Knoxville, TN); Lackey, Walter J. (Oak Ridge, TN); Blanco, Raymond E. (Oak Ridge, TN); Stinton, David P. (Knoxville, TN)
Photovoltaic properties of multi-walled carbon nanotubes deposited on n-doped silicon
Multi-wall carbon nanotubes (MWCNTs), grown by catalytic chemical vapor deposition (CCVD) over Fe supported on alumina catalyst, using isobutane as feedstock, are dispersed in aqueous solutions of sodium dodecyl sulfate. Stable and highly photosensitive ... Keywords: Hybrid solar cells, Multi-walled carbon nanotubes, Silicon heterojunctions
A. Arena; N. Donato; G. Saitta; S. Galvagno; C. Milone; A. Pistone
The field emission properties of graphene aggregates films deposited on Fe-Cr-Ni alloy substrates
The graphene aggregates films were fabricated directly on Fe-Cr-Ni alloy substrates by microwave plasma chemical vapor deposition system (MPCVD). The source gas was a mixture of H2 and CH4 with flow rates of 100 sccm and 12 sccm, ...
Zhanling Lu; Wanjie Wang; Xiaotian Ma; Ning Yao; Lan Zhang; Binglin Zhang
Radionuclide deposition control
The deposition of radionuclides manganese-54, cobalt-58 and cobalt-60 from liquid sodium coolant is controlled by providing surfaces of nickel or high nickel alloys to extract the radionuclides from the liquid sodium, and by providing surfaces of tungsten, molybdenum or tantalum to prevent or retard radionuclide deposition.
Brehm, William F. (Richland, WA); McGuire, Joseph C. (Richland, WA)
Improved Retrieval of Integrated Water Vapor from Water Vapor Radiometer Measurements Using Numerical Weather Prediction Models
Water vapor radiometer (WVR) retrieval algorithms require a priori information on atmospheric conditions along the line of sight of the radiometer in order to derive opacities from observed brightness temperatures. This paper's focus is the mean ...
Steven R. Chiswell; Steven Businger; Michael Bevis; Fredrick Solheim; Christian Rocken; Randolph Ware
Effects of capillarity and vapor adsorption in the depletion of vapor-dominated geothermal reservoirs
Vapor-dominated geothermal reservoirs in natural (undisturbed) conditions contain water as both vapor and liquid phases. The most compelling evidence for the presence of distributed liquid water is the observation that vapor pressures in these systems are close to saturated vapor pressure for measured reservoir temperatures (White et al., 1971; Truesdell and White, 1973). Analysis of natural heat flow conditions provides additional, indirect evidence for the ubiquitous presence of liquid. From an analysis of the heat pipe process (vapor-liquid counterflow) Preuss (1985) inferred that effective vertical permeability to liquid phase in vapor-dominated reservoirs is approximately 10{sup 17} m{sup 2}, for a heat flux of 1 W/m{sup 2}. This value appears to be at the high end of matrix permeabilities of unfractured rocks at The Geysers, suggesting that at least the smaller fractures contribute to liquid permeability. For liquid to be mobile in fractures, the rock matrix must be essentially completely liquid-saturated, because otherwise liquid phase would be sucked from the fractures into the matrix by capillary force. Large water saturation in the matrix, well above the irreducible saturation of perhaps 30%, has been shown to be compatible with production of superheated steam (Pruess and Narasimhan, 1982). In response to fluid production the liquid phase will boil, with heat of vaporization supplied by the reservoir rocks. As reservoir temperatures decline reservoir pressures will decline also. For depletion of ''bulk'' liquid, the pressure would decline along the saturated vapor pressure curve, while for liquid held by capillary and adsorptive forces inside porous media, an additional decline will arise from ''vapor pressure lowering''. Capillary pressure and vapor adsorption effects, and associated vapor pressure lowering phenomena, have received considerable attention in the geothermal literature, and also in studies related to geologic disposal of heat generating nuclear wastes, and in the drying of porous materials. Geothermally oriented studies were presented by Chicoine et al. (1977), Hsieh and Ramey (1978, 1981), Herkelrath et al. (1983), and Nghiem and Ramey (1991). Nuclear waste-related work includes papers by Herkelrath and O'Neal (1985), Pollock (1986), Eaton and Bixler (1987), Pruess et al. (1990), Nitao (1990), and Doughty and E'ruess (1991). Applications to industrial drying of porous materials have been discussed by Hamiathy (1969) arid Whitaker (1977). This paper is primarily concerned with evaluating the impact of vapor pressure lowering (VPL) effects on the depletion behavior of vapor-dominated reservoirs. We have examined experimental data on vapor adsorption and capillary pressures in an effort to identify constitutive relationships that would be applicable to the tight matrix rocks of vapor-dominated systems. Numerical simulations have been performed to evaluate the impact of these effects on the depletion of vapor-dominated reservoirs.
Pruess, Karsten; O'Sullivan, Michael
Moisture Durability of Vapor Permeable Insulating Sheathing (Fact Sheet)
In this project, Building America team Building Science Corporation researched some of the ramifications of using exterior, vapor permeable insulation on retrofit walls with vapor permeable cavity insulation. Retrofit strategies are a key factor in reducing exterior building stock consumption.
The Effect of vapor subcooling on film condensation of metals
This work presents an analysis of the interfacial "vapor-condensate" temperature distribution, which includes the effect of subcooling (supersaturation) in the vapor. Experimental data from previous investigators for ...
Fedorovich, Eugene D.
Waste tank headspace gas and vapor characterization reference guide
This document is to serve as a reference guide for gas and vapor sample results presented in tank characterization reports. It describes sampling equipment, devices, and protocols, and sample collection and analysis methods common to all vapor samples.
Huckaby, J.L.
Microwave Plasma Chemical Vapor Depositon of Nano-Structured...
Plasma Chemical Vapor Depositon of Nano-Structured SnC Composite Thin-Film anodes for Li-ion Battteries Title Microwave Plasma Chemical Vapor Depositon of Nano-Structured SnC...
Estimating the Atmospheric Water Vapor Content from Sun Photometer Measurements
The differential absorption technique for estimating columnar water vapor values from the analysis of sunphotometric measurements with wide- and narrowband interferential filters centered near 0.94 ?m is discussed and adapted. Water vapor line ...
Artemio Plana-Fattori; Michel Legrand; Didier Tanr�; Claude Devaux; Anne Vermeulen; Philippe Dubuisson
Atmospheric Solar Heating Rate in the Water Vapor Bands
The total absorption of solar radiation by water vapor in clear atmosphere is parameterized as a simple function of the scaled water vapor amount. For applications to cloudy and hazy atmospheres, the flux-weighted k-distribution functions are ...
Ming-Dah Chou
Modeling engine oil vaporization and transport of the oil vapor in the piston ring pack on internal combustion engines
A model was developed to study engine oil vaporization and oil vapor transport in the piston ring pack of internal combustion engines. With the assumption that the multi-grade oil can be modeled as a compound of several ...
Perspectives on Deposition Velocity
Deposition Deposition Velocity ... Going down the rabbit hole to explain that sinking feeling Brian DiNunno, Ph.D. Project Enhancement Corporation June 6 th , 2012 Discussion Framework Development of the HSS Deposition Velocity Safety Bulletin Broader discussion of appropriate conservatism within dispersion modeling and DOE-STD-3009 DOE-STD-3009 Dose Comparison "General discussion is provided for source term calculation and dose estimation, as well as prescriptive guidance for the latter. The intent is that calculations be based on reasonably conservative estimates of the various input parameters." - DOE-STD-3009, Appendix A.3 DOE-STD-3009 Dispersion
Advanced Membrane Systems: Recovering Wasteful and Hazardous Fuel Vapors at the Gasoline Tank
Energy.gov (U.S. Department of Energy (DOE))
Case study covering Compact Membrane Systems, Inc. and its membrane vapor processor that recovers fuel vapors from gasoline refueling.
Vapor-pressure lowering in geothermal systems
The water vapor-pressure lowering phenomenon in porous media was investigated for a range of temperatures by measuring vapor pressure vs. mass of water adsorbed in consolidated sandstone cores and unconsolidated silica sands. Experimental results showed that the mass of water adsorbed on the rock surface is much more than the amount of pore steam. Results also revealed that the water adsorption is caused mainly by micropores in the porous medium. Measurement of the mass of methane and ethane adsorbed on dry rocks showed that the amount of adsorption is not great in comparison with the pore gas. It was found that adsorption data for water/sandstone core studies could be normalized with respect to temperature. Although this appears not to have been reported previously, it does agree in principle with findings for solid powders with micropores. Another interesting result was that reanalysis of previous studies of capillarity in sandstones indicates that experimental data probably were influenced mostly by adsorption.
Hsieh, C.H.; Ramey, H.J. Jr.
Hydrocarbon pool and vapor fire data analysis
The flame geometry and thermal radiation data from a series of large scale experiments involving liquefied petroleum gas (LPG) and gasoline spills on water were analyzed. The experiments were conducted at the Naval Weapons Center, China Lake, California. Two types of fires have been studied; namely, pool fires and vapor fires. The spill quantity varied from 4 m/sup 3/ to approximately 6 m/sup 3/. The LPG pool fire flame height to diameter ratio were between 3.5 and 4.5. The gasoline flame height was about 2. The flame emissive powers for LPG pool fires ranged from 78 kW/m/sup 2/ to 115 kW/m/sup 2/. The average surface emissive power for gasoline pool fire was 40 kW/m/sup 2/. The LPG vapor fire emissive power ranged from 159 to 269 kW/m/sup 2/. 63 figures, 13 tables.
Mudan, K.S.
BWR Fuel Deposit Evaluation
With zinc injection to BWR feedwater for plant radiation dose reduction, fuel deposits often contain significant amounts of zinc and the inner layers of deposits become more adherent to the cladding. Fuel surveillance programs have revealed thick tenacious crud with surface spallation at several plants. This project determined the chemical composition and morphological features of crud flake samples from Duane Arnold Cycle 17 and Browns Ferry 2 Cycle 12 and compared the data with those obtained from othe...
A description of the Experimental Boiling Water Reactor vapor-recovery system is given. The seal air operating pressures, temperatures, and moisture content were measured. Air flow through the seals was measured and seal wear was assessed. Assuming direct-cycle D/sub 2/ operation, the seals were evaluated relative to the amount of D/sub 2/ leakage that would be controlled (C.J.G.)
Gariboldi, R.J.; Jacobson, D.R.
Transport properties of fission product vapors
Kinetic theory of gases is used to calculate the transport properties of fission product vapors in a steam and hydrogen environment. Provided in tabular form is diffusivity of steam and hydrogen, viscosity and thermal conductivity of the gaseous mixture, and diffusivity of cesium iodide, cesium hydroxide, diatomic tellurium and tellurium dioxide. These transport properties are required in determining the thermal-hydraulics of and fission product transport in light water reactors.
Im, K.H.; Ahluwalia, R.K.
Copper vapor laser modular packaging assembly
A modularized packaging arrangement for one or more copper vapor lasers and associated equipment is disclosed herein. This arrangement includes a single housing which contains the laser or lasers and all their associated equipment except power, water and neon, and means for bringing power, water, and neon which are necessary to the operation of the lasers into the container for use by the laser or lasers and their associated equipment.
Alger, Terry W. (Tracy, CA); Ault, Earl R. (Dublin, CA); Moses, Edward I. (Castro Valley, CA)
A modularized packaging arrangement for one or more copper vapor lasers and associated equipment is disclosed herein. This arrangement includes a single housing which contains the laser or lasers and all their associated equipment except power, water and neon, and means for bringing power, water, and neon which are necessary to the operation of the lasers into the container for use by the laser or lasers and their associated equipment. 2 figs.
Alger, T.W.; Ault, E.R.; Moses, E.I.
DuPont Chemical Vapor Technical Report
DuPont Safety Resources was tasked with reviewing the current chemical vapor control practices and providing preventive recommendations on best commercial techniques to control worker exposures. The increased focus of the tank closure project to meet the 2024 Tri-Party Agreement (TPA) milestones has surfaced concerns among some CH2MHill employees and other interested parties. CH2MHill is committed to providing a safe working environment for employees and desires to safely manage the tank farm operations using appropriate control measures. To address worker concerns, CH2MHill has chartered a ''Chemical Vapors Project'' to integrate the activities of multiple CH2MHill project teams, and solicit the expertise of external resources, including an independent Industrial Hygiene expert panel, a communications consultant, and DuPont Safety Resources. Over a three-month time period, DuPont worked with CH2MHill ESH&Q, Industrial Hygiene, Engineering, and the independent expert panel to perform the assessment. The process included overview presentations, formal interviews, informal discussions, documentation review, and literature review. DuPont Safety Resources concluded that it is highly unlikely that workers in the tank farms are exposed to chemicals above established standards. Additionally, the conventional and radiological chemistry is understood, the inherent chemical hazards are known, and the risk associated with chemical vapor exposure is properly managed. The assessment highlighted management's commitment to addressing chemical vapor hazards and controlling the associated risks. Additionally, we found the Industrial Hygiene staff to be technically competent and well motivated. The tank characterization data resides in a comprehensive database containing the tank chemical compositions and relevant airborne concentrations.
Passive vapor transport solar heating systems
In the systems under consideration, refrigerant is evaporated in a solar collector and condensed in thermal storage for space or water heating located within the building at a level below that of the collector. Condensed liquid is lifted to an accumulator above the collector by the vapor pressure generated in the collector. Tests of two systems are described, and it is concluded that one of these systems offers distinct advantages.
Hedstrom, J.C.; Neeper, D.A.
EMSL: Capabilities: Deposition and Microfabrication
Deposition and Microfabrication Deposition and Microfabrication Additional Information Meet the Deposition and Microfabrication Experts Related EMSL User Projects Deposition and Microfabrication Tools are Applied to all Science Themes Deposition and Microfabrication brochure Designed to augment research important to a variety of disciplines, EMSL's Deposition and Microfabrication Capability tackles serious scientific challenges from a microscopic perspective. From deposition instruments that emphasize oxide films and interfaces to a state-of-the-art microfabrication suite, EMSL has equipment to tailor surfaces, as diverse as single-crystal thin films or nanostructures, or create the microenvironments needed for direct experimentation at micron scales. Users benefit from coupling deposition and microfabrication applications
The production of niobium-tin powders by vapor-deposition processes
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Plasma and Ion Assistance in Physical Vapor Deposition: A Historical Perspective
sources were taken from space propulsion and applied to thinspace programs, where ion thrusters were developed for satellite propulsion [
In-situ formation of multiphase electron beam physical vapor deposited barrier coatings for turbine components
A turbine component (10), such as a turbine blade, is provided which is made of a metal alloy (22) and a base columnar thermal barrier coating (20) on the alloy surface, where a heat resistant ceramic oxide sheath material (32' or 34') covers the columns (28), and the sheath material is the reaction product of a precursor ceramic oxide sheath material and the base thermal barrier coating material.
Subramanian, Ramesh (Oviedo, FL)
Polymers via chemical vapor deposition and their application to organic photovoltaics
There is emerging interest in the ability to fabricate organic photovoltaics (OPVs) on flexible, lightweight substrates, which could lower the cost of installation and enable new form factors for deployment. However, ...
Barr, Miles Clark
The Theoretical Basis for the Parameterization of Ice Crystal Habits: Growth by Vapor Deposition
A theoretical analysis of surface kinetic and gas-phase diffusional effects permits the growth rates and habits of ice crystals to be specified in a self-consistent way. The analysis makes use of the fact that the difference between the ...
Jen-Ping Chen; Dennis Lamb
Oxidative and initiated chemical vapor deposition for application to organic electronics
Since the first discovery of polymeric conductors in 1977, the research area of "organic electronics" has grown dramatically. However, methods for forming thin films comprised solely of conductive polymers are limited by ...
Im, Sung Gap
Desktop systems for manufacturing carbon nanotube films by chemical vapor deposition
Carbon nanotubes (CNTs) exhibit exceptional electrical, thermal, and mechanical properties that could potentially transform such diverse fields as composites, electronics, cooling, energy storage, and biological sensing. ...
Kuhn, David S. (David Scott)
Four-well highly strained quantum cascade lasers grown by metal-organic chemical vapor deposition
We demonstrate a novel four-well injectorless design with short wavelength (5.5 mum) and room temperature operation utilizing highly strained Ga[subscript 0.35] In[subscript 0.6] As/Al[subscript 0.70] In[subscript 0.30]As ...
Hsu, Allen Long
Ed. ), Handbook of Plasma Immersion Ion Implantation andK. G. M�ller, IEEE Trans. Plasma Sci. [76] I. I. Beilis, R.449. [79] J. Hopwood, Phys. Plasmas 5 (1998) 1624. [80] M.
or Rene-N5 during engine operation. The current method for YSZ fabrication for TBC applications is by air. The solution was delivered continuously by a syringe pump through a poppet-seal relief valve
Chemical vapor deposition of conjugated polymeric thin films for photonic and electronic applications
(cont.) Conjugated polymers have delocalized electrons along the backbone, facilitating electrical conductivity. As thin films, they are integral to organic semiconductor devices emerging in the marketplace, such as flexible ...
Lock, John P
High-rate chemical vapor deposition of nanocrystalline silicon carbide films by radio frequency thermal plasma
by liquid spray injection of disilanes into an argonhydrogen RF plasma operat- ing at 2040 kPa [4]. Here
Zachariah, Michael R.
Ultrahigh growth rate of epitaxial silicon by chemical vapor deposition at low temperature with neopentasilane
- iane SiH4 to disilane Si2H6 , to trisilane, Si3H8 2 leads to increased epitaxy growth rates at the same growth rate was 0.6 nm/min, and the disilane growth rate was 8 nm/min. In this work, we explored the use
.e. from silane to disilane to trisilane) the silicon growth rate increases for the same experimental
Chemical Vapor Deposition Epitaxy of Silicon-based Materials using Neopentasilane
of dichlorosilane, silane, disilane, and neopentasilane vs. inverse temperature observed in our lab on Si(100 dichlorosilane is not observable, and that for silane and disilane were 0.6 and 8 ECS Transactions, 16 (10) 799 sources of dichlorosilane (DCS), silane, disilane and neopentasilane (NPS) precursor on (100) silicon
BS> The use of titanium getter pumping for large vacuum systems is described. Techniques were developed which give sorption rates approaching the maximum theoretically possible for many of the chemically active gases. A simple method of determining sticking fractions is descrnkbed. Sticking fractions for hydrogen, deuterium, oxygen, nitrogen, carbon nknonoxnkde, carbon dioxide, and methane are given for various films. The capacity and sorption characteristics for these films are shown. Simple and reliable resistance-heated titanium evapdorators are described. lt was demonstrated that the pumping methods described provide outstanding performance and are both reliable and practical. (auth)
and optical properties such as high mobility electron transistors and far ultraviolet light emitting diodes
Mellor-Crummey, John
Reduction of multipactor in RF ceramic windows using a simple titanium-vapor deposition system
A brief description of multipactor is followed by a discussion of design parameters for a titanium sublimation system. Efforts to correlate operating parameters (time, temperature, etc.) with thickness of coated titanium are reported. Rutherford backscattering thickness measurements are described and reported.
Primdahl, K.; Kustom, R.; Maj, J.
Four-point electrical resistivity measurement����������..34with negligible electrical resistivity due to scattering3] . 4.3 Four-point electrical resistivity measurement: For
Low temperature chemical vapor deposition of Co thin films from Co2(CO)8
, products obtained from hydrothermal upgrading, Fisher-Tropsch diesel from bio-based synthesis gas and bio by a Karl Fisher titration. For the Karl Fisher titrations a 787 KF Titrino device from Metrohm was used
Wang, Gwo-Ching
Development of a spatially controllable chemical vapor deposition reactor with combinatorial processing capabilities
-to-segment gas concentration gradient across the wafer surface in the gap region. Third, residual gas analysis was equipped with a lamp heater and quartz window sieve showerhead. As part of the prototype modifications, we replaced the lamp heater with a substrate resistance heater and the quartz window a Author to whom
Graphene-on-Insulator Transistors Made Using C on Ni Chemical-Vapor Deposition
Graphene transistors are made by transferring a thin graphene film grown on Ni onto an insulating SiO[subscript 2] substrate. The properties and integration of these graphene-on-insulator transistors are presented and ...
Keast, Craig L.
Annalen der Physik und Chemie 66 (1843) 376. [13] A. W.Zeitschrift f�r Physikalische Chemie 205 (1956) 349. [36] J.
Nickel catalyst faceting in plasma-enhanced direct current chemical vapor deposition of carbon nanofibers
, based on hydrogen production via coal gasification with sequestration and possibly via biomass gasification, that can take advantage of economies of scale, will be needed to meet increased hydrogen demand processing capabilities of interest are high frequency microwave heating and fiber optic laser techniques
Paris-Sud XI, Université de
Thermodynamic evaluation of the CdTe deposition by an elemental co-evaporation method under isothermal transport conditions
Thermodynamic potential diagrams were used to predict the conditions for depositing cadmium telluride thin films from two independent elemental sources, Cd and Te, while keeping sources and substrate at the same temperature. The potential diagrams also allowed the evaluation of the influence of gaseous contaminants, such as oxygen, on the formed condensed phases. The method may be applied to the deposition of other compounds as long as their vapor pressures are much smaller than the vapor pressures of the constituent elements. The thermodynamic calculation suggested that the film may be deposited under total pressure of 10-4 mbar and at temperatures as low as 450 deg. C. This total pressure is easily achieved by a mechanical pump and the low temperature range allows the use of low cost glass substrates. The preliminary results showed that the films deposited under the conditions predicted by the thermodynamic calculations were uniform and crystalline, as confirmed by scanning electron microscopy and X-ray diffraction.
Ribeiro, M.C.R. [Pontificia Universidade Catolica do Rio de Janeiro, Departamento de Ciencia dos Materiais e Metalurgia, Rua Marques de Sao Vicente, 225 Gavea, 22453-900 Rio de Janeiro, RJ (Brazil)]. E-mail: email@example.com; Cruz, L.R. [Instituto Militar de Engenharia, Departamento de Engenharia Mecanica e de Materiais, Praca General Tiburcio, 80 Urca, 22290-270 Rio de Janeiro, RJ (Brazil); Avillez, R.R. de [Pontificia Universidade Catolica do Rio de Janeiro, Departamento de Ciencia dos Materiais e Metalurgia, Rua Marques de Sao Vicente, 225 Gavea, 22453-900 Rio de Janeiro, RJ (Brazil)
Properties of Amorphous Carbon Microspheres Synthesised by Palm Oil-CVD Method
Amorphous carbon microspheres were synthesized using a dual-furnace chemical vapour deposition method at 800-1000 deg. C. Palm oil-based cooking oil (PO) and zinc nitrate solution was used as a carbon source and catalyst precursor, respectively with PO to zinc nitrate ratio of 30:20 (v/v) and a silicon wafer as the sample target. Regular microsphere shape of the amorphous carbons was obtained and a uniform microsphere structure improved as the carbonization temperature increased from 800 to 1000 deg. C. At 800 deg. C, no regular microspheres were formed but more uniform structure is observed at 900 deg. C. Generally the microspheres size is uniform when the heating temperature was increased to 1000 deg. C, but the presence of mixed sizes can still be observed. X-ray diffraction patterns show the presence of oxide of carbon, ZnO phase together with Zn oxalate phase. Raman spectra show two broad peaks characteristic to amorphous carbon at 1344 and 1582 cm{sup -1} for the D and G bands, respectively. These bands become more prominent as the preparation temperature increased from 800 to 1000 deg. C. This is in agreement with the formation of amorphous carbon microspheres as shown by the FESEM study and other Zn-based phases as a result of the oxidation process of the palm oil as the carbon source and the zinc nitrate as the catalyst precursor, respectively.
Zobir, S. A. M. [Faculty of Applied Sciences, (UiTM), 40450 Shah Alam, Selangor (Malaysia); Nano-SciTech Centre, (UiTM), 40450 Shah Alam, Selangor (Malaysia); Zainal, Z. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400UPM, Serdang, Selangor (Malaysia); Sarijo, S. H. [Faculty of Applied Sciences, (UiTM), 40450 Shah Alam, Selangor (Malaysia); Institute of Science, Universiti Teknologi MARA Malaysia, (UiTM), 40450 Shah Alam, Selangor (Malaysia); Rusop, M. [Nano-SciTech Centre, (UiTM), 40450 Shah Alam, Selangor (Malaysia); Institute of Science, Universiti Teknologi MARA Malaysia, (UiTM), 40450 Shah Alam, Selangor (Malaysia)
Instrument Series: Deposition and Microfabrication
Deposition and Microfabrication Deposition and Microfabrication Sputter Deposition System Only available at EMSL, the Discovery ® Deposition System has been customized to be a fully automated multi-functional "hybrid" instrument with several modes for thin film processing, including multi-target sputtering, effusion cell deposition, electron beam deposition, and in-situ reflection high-energy electron diffraction (RHEED) materials characterization. Unlike most systems, the Discovery ® Deposition System's unique configuration offers operational flexibility, efficiency, and control, allowing a range of applications and materials to be processed simultaneously. Because it is software controlled, users can provide their own "recipes" and have a complete log of what happens throughout the
Cathodic Arc Plasma Deposition
Cathodic Arc Plasma Deposition Cathodic Arc Plasma Deposition André Anders Lawrence Berkeley National Laboratory, University of California, 1 Cyclotron Road, Mailstop 53, Berkeley, California 94720 email@example.com Abstract Cathodic arc plasma deposition is one of oldest coatings technologies. Over the last two decades it has become the technology of choice for hard, wear resistant coatings on cutting and forming tools, corrosion resistant and decorative coatings on door knobs, shower heads, jewelry, and many other substrates. The history, basic physics of cathodic arc operation, the infamous macroparticle problem and common filter solutions are reviewed. Cathodic arc plasmas stand out due to their high degree of ionization, with important consequences for film nucleation, growth, and efficient utilization of substrate bias. The
Hot-Wire Deposition of Hydrogenated Nanocrystalline SiGe Films for Thin-Film Si Based Solar Cells
Hot-Wire Deposition of Hydrogenated Nanocrystalline SiGe Films for Thin-Film Si Based Solar Cells bandgap absorber in an a-Si/a-SiGe/nc-SiGe(nc- Si) triple-junction solar cell due to its higher optical investigations of nc-SiGe:H thin films made by hot-wire chemical vapor deposition (HWCVD) with a coil
Atmospheric Plasma Deposition of Diamond-like Carbon Coatings
DLC coatings in a low-pressure environment. For example, ion beam processes are widely utilized since the ion bombardment is thought to promote denser sp3-bonded carbon networks. Other processes, such as sputtering, are better suited for coating large parts [29,30,44]. However, the deposition of DLC in a vacuum system has several disadvantages, including high equipment cost and restrictions on the size and shape of material that may be treated. The deposition of DLC at atmospheric pressure has been demonstrated by several researchers. Izake, et al [53] and Novikov and Dymont [54] have demonstrated an electrochemical process that is carried out with organic compounds such as methanol and acetylene dissolved in ammonia. This process requires that the substrates be immersed in the liquid [53-54]. The atmospheric pressure deposition of DLC was also demonstrated by Kulik, et al. utilizing a plasma torch. However, this process requires operating temperatures in excess of 800 oC [55]. In this report, we investigate the deposition of diamond-like carbon films using a low temperature, atmospheric pressure plasma-enhanced chemical vapor deposition (PECVD) process. The films were characterized by solid-state carbon-13 nuclear magnetic resonance (13C NMR) and found to have a ratio of sp2 to sp3 carbon of 43 to 57%. The films were also tested for adhesion, coefficient of friction, and dielectric strength.
Ladwig, Angela
Vapor port and groundwater sampling well
A method and apparatus have been developed for combining groundwater monitoring wells with unsaturated-zone vapor sampling ports. The apparatus allows concurrent monitoring of both the unsaturated and the saturated zone from the same well at contaminated areas. The innovative well design allows for concurrent sampling of groundwater and volatile organic compounds (VOCs) in the vadose (unsaturated) zone from a single well, saving considerable time and money. The sample tubes are banded to the outer well casing during installation of the well casing. 10 figs.
Hubbell, J.M.; Wylie, A.H.
A method and apparatus has been developed for combining groundwater monitoring wells with unsaturated-zone vapor sampling ports. The apparatus allows concurrent monitoring of both the unsaturated and the saturated zone from the same well at contaminated areas. The innovative well design allows for concurrent sampling of groundwater and volatile organic compounds (VOCs) in the vadose (unsaturated) zone from a single well, saving considerable time and money. The sample tubes are banded to the outer well casing during installation of the well casing.
Hubbell, Joel M. (Idaho Falls, ID); Wylie, Allan H. (Idaho Falls, ID)
Copper vapor laser acoustic thermometry system
A copper vapor laser (CVL) acoustic thermometry system is disclosed. The invention couples an acoustic pulse a predetermined distance into a laser tube by means of a transducer and an alumina rod such that an echo pulse is returned along the alumina rod to the point of entry. The time differential between the point of entry of the acoustic pulse into the laser tube and the exit of the echo pulse is related to the temperature at the predetermined distance within the laser tube. This information is processed and can provide an accurate indication of the average temperature within the laser tube.
Galkowski, J.J.
Photochemical studies of alkali halide vapors
Thesis. An apparatus has been constructed for studying the photodissociation of alkali halides to produce excited alkali metal atoms. The key component is a low pressure H/sub 2/ arc continuum uv source. Radiation from this source, modulated by a chopping wheel and analyzed by a monochromator, enters a cell containing the alkali halide vapor. In the appropriate wavelength range, photodissociation occurs to produce the alkali atom in an excited /sup 2/p state, the flourescence from which is detected by a photomultiplier-lock-in amplifier combination. (auth)
Earl, B.L.
ARM - Field Campaign - Fall 1997 Water Vapor IOP
Water Vapor IOP Water Vapor IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Fall 1997 Water Vapor IOP 1997.09.15 - 1997.10.05 Lead Scientist : Henry Revercomb For data sets, see below. Summary The Water Vapor IOP was conducted as a follow-up to a predecessor IOP on water vapor held in September 1996. This IOP relied heavily on both ground-based guest and CART instrumentation and in-situ aircraft and tethered sonde/kite measurements. Primary operational hours were from 6 p.m. Central until at least midnight, with aircraft support normally from about 9 p.m. until midnight when available. However, many daytime measurements were made to support this IOP. The first Water Vapor IOP primarily concentrated on the atmosphere's lowest
Method and apparatus for concentrating vapors for analysis
A pre-concentration device and a method are disclosed for concentrating gaseous vapors for analysis. Vapors sorbed and concentrated within the bed of the pre-concentration device are thermally desorbed, achieving at least partial separation of the vapor mixtures. The pre-concentration device is suitable, e.g., for pre-concentration and sample injection, and provides greater resolution of peaks for vapors within vapor mixtures, yielding detection levels that are 10-10,000 times better than direct sampling and analysis systems. Features are particularly useful for continuous unattended monitoring applications. The invention finds application in conjunction with, e.g., analytical instruments where low detection limits for gaseous vapors are desirable.
Analysis of the transient compressible vapor flow in heat pipe
The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual vapor flow in cylindrical heat pipes. A good comparison of the present transient results for the simulated heat pipe vapor flow with the previous results of a two-dimensional numerical model is achieved and the steady state results are in agreement with the existing experimental data. The transient behavior of the vapor flow under subsonic, sonic, and supersonic speeds and high mass flow rates are successfully predicted. The one-dimensional model also describes the vapor flow dynamics in cylindrical heat pipes at high temperatures.
Jang, J.H.; Faghri, A. [Wright State Univ., Dayton, OH (United States); Chang, W.S. [Wright Research and Development Center, Wright-Patterson, OH (United States)
Interfacial instability induced by lateral vapor pressure fluctuation in bounded thin liquid-vapor layers
We study an instability of thin liquid-vapor layers bounded by rigid parallel walls from both below and above. In this system, the interfacial instability is induced by lateral vapor pressure fluctuation, which is in turn attributed to the effect of phase change: evaporation occurs at the hotter portion of the interface and condensation at the colder one. The high vapor pressure drives the liquid away and the low one pulls it up. A set of equations describing the temporal evolution of the interface of the liquid-vapor layers is derived. This model neglects the effect of mass loss or gain at the interface and guarantees the mass conservation of the liquid layer. The result of linear stability analysis of the model shows that the presence of the pressure dependence of the local saturation temperature suppresses the growth of long-wave disturbances. We find the stability criterion, which suggests that only slight temperature gradients are sufficient to overcome the stabilizing gravitational effect for a water an...
Kanatani, Kentaro
Method for controlling corrosion in thermal vapor injection gases
An improvement in the method for producing high pressure thermal vapor streams from combustion gases for injection into subterranean oil producing formations to stimulate the production of viscous minerals is described. The improvement involves controlling corrosion in such thermal vapor gases by injecting water near the flame in the combustion zone and injecting ammonia into a vapor producing vessel to contact the combustion gases exiting the combustion chamber.
Sperry, John S. (Houston, TX); Krajicek, Richard W. (Houston, TX)
Mercury Vapor At Haleakala Volcano Area (Thomas, 1986) | Open Energy
Mercury Vapor At Haleakala Volcano Area (Thomas, 1986) Mercury Vapor At Haleakala Volcano Area (Thomas, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor At Haleakala Volcano Area (Thomas, 1986) Exploration Activity Details Location Haleakala Volcano Area Exploration Technique Mercury Vapor Activity Date Usefulness not indicated DOE-funding Unknown Notes The field survey program on the northwest rift zone consisted of soil mercury and radon emanometry surveys, groundwater temperature and chemistry studies, Schlumberger resistivity soundings and self-potential profiles. Geophysical and geochemical surveys along this rift (southwest) were limited by difficult field conditions and access limitations. The geophysical program consisted of one Schlumberger sounding, one
Mercury Vapor At Lassen Volcanic National Park Area (Varekamp...
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Mercury Vapor At Mickey Hot Springs Area (Varekamp & Buseck,...
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Mercury Vapor At Breitenbush Hot Springs Area (Varekamp & Buseck...
Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor At Breitenbush Hot Springs Area (Varekamp & Buseck, 1983) Exploration Activity...
Mercury Vapor At Vale Hot Springs Area (Varekamp & Buseck, 1983...
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Interaction of sodium vapor and graphite studied by ...
The kinetics of the reaction between graphite and sodium vapor is analyzed with support ... High temperature compression test to determine the anode paste�...
Optimal Control of Vapor Extraction of Heavy Oil.
??Vapor extraction (Vapex) process is an emerging technology for viscous oil recovery that has gained much attention in the oil industry. However, the oil production� (more)
Muhamad, Hameed
ARM - Field Campaign - ARM-FIRE Water Vapor Experiment
Order Data Browell, Edward LASE Order Data Gutman, Seth GPS Order Data Richardson, Scott Chilled Mirror Order Data Sachse, G. Water Vapor Order Data Schmidlin, Francis CM Sondes...
Measurements of Vapor Pressures and PVT Properties for n ...
Page 1. Measurements of Vapor Pressures and PVT Properties for n-Butane from 280 to 440 K at Pressures to 200 MPa ...
Molecular restrictions for human eye irritation by chemical vapors
and reactive airborne chemicals. Pharmacol. Toxicol. 1998;WL. Chemesthesis: The Common Chemical Sense. In: Finger TE,MH. Quantification of chemical vapors in chemosensory
Cometto-Muniz, J. Enrique; Cain, William S.; Abraham, Michael H.
Raman Lidar Measurements of Aerosols and Water Vapor During the...
Raman Lidar Measurements of Aerosols and Water Vapor During the May 2003 Aerosol IOP R. A. Ferrare National Aeronautics and Space Administration Langley Research Center Hampton,...
Cesium vapor cycle for an advanced LMFBR
A review indicates that a cesium vapor topping cycle appears attractive for use in the intermediate fluid circuit of an advanced LMFBR designed for a reactor outlet temperature of 1250$sup 0$F or more and would have the following advantages: (1) it would increase the thermal efficiency by about 5 to 10 points (from approximately 40 percent to approximately 45 to 50 percent) thus reducing the amount of waste heat rejected to the environment by 15 to 30 percent. (2) the higher thermal efficiency should reduce the overall capital cost of the reactor plant in dollars per kilowatt. (3) the cesium can be distilled out of the intermediate fluid circuit to leave it bone-dry, thus greatly reducing the time and cost of maintenance work (particularly for the steam generator). (4) the large volume and low pressure of the cesium vapor region in the cesium condenser-steam generator greatly reduces the magnitude of pressure fluctuations that might occur in the event of a leak in a steam generator tube, and the characteristics inherent in a condenser make it easy to design for rapid concentration of any noncondensibles that may form as a consequence of a steam leak into the cesium region so that a steam leak can be detected easily in the very early stages of its development. (auth)
Fraas, A.P.
Reactions of atmospheric vapors with lunar soil
Detailed experimental data have been acquired for the hydration of the surfaces of lunar fines. Inert vapor adsorption has been employed to measure the surface properties (surface energy, surface area, porosity, etc.) and changes wrought in the hydration-dehydration processes. Plausible mechanisms have been considered and the predominant process involves hydration of the metamict metallosilicate surfaces to form a hydrated laminar structure akin to terrestrial clays. Additional credence for this interpretation is obtained by comparison to existing geochemical literature concerning terrestrial weathering of primary metallosilicates. The surface properties of the hydrated lunar fines are compared favorably to those of terrestrial clay minerals. In addition, experimental results are given to show that fresh disordered surfaces of volcanic sand react with water vapor in a manner virtually identical to the majority of the lunar fines. The results show that ion track etching and/or grain boundary attack are minor contributions in the weathering of lunar fines in the realm of our microgravimetric experimental conditions. 14 references. (auth)
Fuller, E.L. Jr.; Agron, P.A.
Ethanol production by vapor compression distillation
The goal of this project is to develop and demonstrate a one gallon per hour vapor compression distillation unit for fuel ethanol production that can be profitably manufactured and economically operated by individual family units. Vapor compression distillation is already an industrially accepted process and this project's goal is to demonstrate that it can be done economically on a small scale. Theoretically, the process is independent of absolute pressure. It is only necessary that the condenser be at higher pressure than the evaporator. By reducing the entire process to a pressure of approximately 0.1 atmosphere, the evaporation and condensation can occur at near ambient temperature. Even though this approach requires a vacuum pump, and thus will not represent the final cost effective design, it does not require preheaters, high temperature materials, or as much insulation as if it were to operate a near ambient pressure. Therefore, the operation of the ambient temperature unit constitutes the first phase of this project. Presently, the ambient temperature unit is fully assembled and has begun testing. So far it has successfully separated ethanol from a nine to one diluted input solution. However the production rate has been very low.
Ellis, G.S.
Integration of Global Positioning System and Scanning Water Vapor Radiometers for Precipitable Water Vapor and Cloud Liquid Path Estimates
Integration of Global Positioning System and Scanning Integration of Global Positioning System and Scanning Water Vapor Radiometers for Precipitable Water Vapor and Cloud Liquid Path Estimates V. Mattioli and P. Basili Department of Electronic and Information Engineering University of Perugia Perugia, Italy E. R. Westwater Cooperative Institute for Research in Environmental Sciences University of Colorado National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado Introduction In recent years the Global Positioning System (GPS) has proved to be a reliable instrument for measuring precipitable water vapor (PWV) (Bevis et al. 1992), offering an independent source of information on water vapor when compared with microwave radiometers (MWRs), and/or radiosonde
Vapor and gas sampling of Single-Shell Tank 241-A-101 using the Vapor Sampling System
This document presents sampling data resulting from the June 8, 1995, sampling of SST 241-A-101 using the Vapor Sampling System.
Caprio, G.S.
Vapor and gas sampling of single-shell tank 241-SX-106 using the vapor sampling system
This document presents sampling data resulting from the March 24, 1995, sampling of SST 241-SX-106 using the vapor sampling system.
Energy Deposition Using EGS4
are used to model the energy deposition in 0.4 r.l. Ti due to photons produced by the Tesla TRD undulator driven by the 250 GeV Tesla primary electron beam. 1 Energy Deposition...
Bulletin 627 Bulletin 627 BUREAU o b MINES FLAMMABILITY CHARACTERISTICS OF COMBUSTIBLE GASES AND VAPORS By Michael G. Zabetakis DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement,
New Regenerative Cycle for Vapor Compression Refrigeration
SCIENTIFIC REPORT SCIENTIFIC REPORT Title Page Project Title: New Regenerative Cycle for Vapor Compression Refrigeration DOE Award Number: DE-FG36-04GO14327 Document Title: Final Scientific Report Period Covered by Report: September 30, 2004 to September 30, 2005 Name and Address of Recipient Organization: Magnetic Development, Inc., 68 Winterhill Road, Madison, CT 06443, phone: 203-214-7247, fax: 203-421-7948, e-mail: firstname.lastname@example.com Contact Information: Mark J. Bergander, Ph.D., P.E., Principal Investigator, phone: 203-214-7247, fax: 203-421-7948, e-mail: email@example.com Project Objective (as stated in the proposal): The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient
How solvent vapors can improve steam floods
Thermal recovery methods depend for their success on the viscosity reduction of heavy crude oils at high temperatures. The viscosity of a heavy oil can also be reduced if it is diluted with a low-viscosity solvent, such as one of the lighter hydrocarbons. It is not surprising that there has been considerable interest in combining the two methods. The process of injecting vaporized solvent with the steam for a gravity drainage type recovery is described here along with a description of the particular phase behavior of steam/solvent mixtures which is beneficial to the process. And computer simulations which compare steam-only and steam/solvent floods under Athabasca-type conditions are overviewed.
Vogel, J. [Vogel, (Jack), Seabrook, TX (United States)
Gas transport model for chemical vapor infiltration
A node-bond percolation model is presented for the gas permeability and pore surface area of the coarse porosity in woven fiber structures during densification by chemical vapor infiltration (CVI). Model parameters include the number of nodes per unit volume and their spatial distribution, and the node and bond radii and their variability. These parameters relate directly to structural features of the weave. Some uncertainty exists in the proper partition of the porosity between ``node`` and ``bond`` and between intra-tow and inter-tow, although the total is constrained by the known fiber loading in the structure. Applied to cloth layup preforms the model gives good agreement with the limited number of available measurements.
Starr, T.L. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States)
Oil shale deposits of Thailand
Oil-shale deposits occur in several areas of Thailand. Perhaps the most important deposit occurs at Mae Sod in Tak Province, West Thailand. Other well-known deposits are Li in Lamphum Province, Ko Kha District, Lampang Province, and Krabi in the southern peninsular region. The geological age of all these deposits is late Tertiary, as demonstrated by the presence of the fossils from the oil shale of the Mae Sod series, e.g., fish of the Ostariophysian family Cyprinidae.
Chakrabarti, A.K.
Thin Film Deposition and Processing
RESONANT FARADAY ROTATION IN A HOT LITHIUM VAPOR By SCOTT RUSSELL WAITUKAITIS A Thesis Submitted: #12;Abstract I describe a study of Faraday rotation in a hot lithium vapor. I begin by dis- cussing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 The Lithium Oven and Solenoid . . . . . . . . . . . . . . . . . 7 3 Theoretical Framework
Cronin, Alex D.
Hybrid Vapor Compression Adsorption System: Thermal Storage Using Hybrid Vapor Compression Adsorption System
HEATS Project: UTRC is developing a new climate-control system for EVs that uses a hybrid vapor compression adsorption system with thermal energy storage. The targeted, closed system will use energy during the battery-charging step to recharge the thermal storage, and it will use minimal power to provide cooling or heating to the cabin during a drive cycle. The team will use a unique approach of absorbing a refrigerant on a metal salt, which will create a lightweight, high-energy-density refrigerant. This unique working pair can operate indefinitely as a traditional vapor compression heat pump using electrical energy, if desired. The project will deliver a hot-and-cold battery that provides comfort to the passengers using minimal power, substantially extending the driving range of EVs.
Low energy ion beam assisted deposition of a spin valve
The spin dependent electron transport in giant magnetoresistive (GMR) multilayers is significantly affected by the atomic scale structure of their interfaces. Devices with atomically flat and chemically sharp interfaces are preferred for magnetic sensor and memory applications. Recent atomic simulations of the atom-by-atom assembly of these devices indicate that near optimal interfacial structures can be created using low energy, ion assisted vapor deposition techniques with ion energies in the 5-10 eV range. A recently developed biased target ion beam deposition system has been used to experimentally test this hypothesis. Prototypical Ta/NiFe/Co/Cu/Co/FeMn/Cu spin valve structures were first grown using (simultaneous) argon ion assistance during deposition of the Co/Cu/Co trilayer part of the spin valve multilayer. Assisting ion energies of around 10 eV resulted in structures with a 30% higher magnetoresistance ratio and significantly reduced coupling field compared to samples grown with no ion assistance or with ion energies above 15 eV. These results are consistent with the atomistic simulation predictions. Other promising ion assistance schemes identified by the simulations were then used to deposit the Ta, NiFe, FeMn, and the top copper layer. A near optimal strategy was identified that resulted in the further improvement of the GMR ratio.
Quan, J. J.; Wolf, S. A.; Wadley, H. N. G. [Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia 22903 (United States)
Worker Protection from Chemical Vapors: Hanford Tank Farms
Chemical vapor emissions from underground hazardous waste storage tanks on the Hanford site in eastern Washington State are a potential concern because workers enter the tank farms on a regular basis for waste retrievals, equipment maintenance, and surveillance. Tank farm contractors are in the process of retrieving all remaining waste from aging single-shell tanks, some of which date to World War II, and transferring it to newer double-shell tanks. During the waste retrieval process, tank farm workers are potentially exposed to fugitive chemical vapors that can escape from tank head-spaces and other emission points. The tanks are known to hold more than 1,500 different species of chemicals, in addition to radionuclides. Exposure assessments have fully characterized the hazards from chemical vapors in half of the tank farms. Extensive sampling and analysis has been done to characterize the chemical properties of hazardous waste and to evaluate potential health hazards of vapors at the ground surface, where workers perform maintenance and waste transfer activities. Worker concerns, risk communication, and exposure assessment are discussed, including evaluation of the potential hazards of complex mixtures of chemical vapors. Concentrations of vapors above occupational exposure limits (OEL) were detected only at exhaust stacks and passive breather filter outlets. Beyond five feet from the sources, vapors disperse rapidly. No vapors have been measured above 50% of their OELs more than five feet from the source. Vapor controls are focused on limited hazard zones around sources. Further evaluations of vapors include analysis of routes of exposure and thorough analysis of nuisance odors. (authors)
Anderson, T.J. [CH2M HILL Hanford Group, Inc. / Environmental Health, Richland, WA (United States)
The Effects of Water Vapor on the Oxidation of Nickel-Base ...
water vapor are compared at temperatures from 700�C to 1100�C. It is shown that water vapor affects the oxidation of such alloys in different ways. Water vapor�...
Water Vapor Flux Measurements from Ground-Based Vertically Pointed Water Vapor Differential Absorption and Doppler Lidars
For the first time, two lidar systems were used to measure the vertical water vapor flux in a convective boundary layer by means of eddy correlation. This was achieved by combining a water vapor differential absorption lidar and a heterodyne wind ...
Andreas Giez; Gerhard Ehret; Ronald L. Schwiesow; Kenneth J. Davis; Donald H. Lenschow
Multi-chamber deposition system
A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.
Jacobson, Richard L. (Roseville, MN); Jeffrey, Frank R. (Shoreview, MN); Westerberg, Roger K. (Cottage Grove, MN)
Stable nitrogen isotope ratios in wet and dry nitrate deposition collected with an artificial tree
Amounts of dry NO{sub 3}-N deposition and N isotope ratios in wet and dry NO{sub 3}-N deposition have been simultaneously determined by examining differences between precipitation collected by open funnels and throughfall collected beneath an artificial Christmas tree. Samples were collected in a forest clearing on Walker Branch Watershed, near Oak Ridge, Tennessee. From mid-summer to early autumn, NO{sub 3}-N fluxes beneath the artificial tree were always greater than those measured in precipitation indicating the tree's effectiveness as a passive collector of dry NO{sub 3}-N deposition. Dry NO{sub 3}-N deposition averaged 60 {+-} 9% of total (wet and dry) deposition. The mean ({+-} SD) calculated {delta}{sup 15}N value for NO{sub 3}-N in dry deposition was + 5.6 {+-} 2.1{per_thousand} (n = 6 sampling periods ranging from 4 to 15 days). On average, this was {approx} 6{per_thousand} heavier than measured {delta}{sup 15}N values for NO{sub 3}-N in precipitation. The calculated {delta}{sup 15}N value for NO{sub 3}-N in dry deposition was consistent with that expected if NO{sub x} precursors to HNO{sub 3} vapor (the major constituent of dry deposition at this site) originated principally from coal combustion.
Garten Jr, Charles T [ORNL
Photovoltaic devices using a-Si:H from higher order silanes. Final subcontract report, September 1, 1983-August 31, 1984
This report describes the preparation of hydrogenated amorphous silicon (a-Si:H) films and photovoltaic devices by chemical vapor deposition (CVD) from higher silanes, and the properties of such films and devices. The motivation for this research is the prospect of preparing by a new technique a-Si:H having electronic properties similar (or superior) to material prepared by the well-known glow discharge technique. Possible advantages of thermal CVD are the absence of ion bombardment, high deposition rates, efficient utilization of feedstock gases, lower levels of impurity incorporation, absence of pinholes, and greater material stability. Photochemical vapor deposition of a-Si:H from disilane is also described and has yielded higher efficiency solar cells than thermal CVD.
Delahoy, A.E.
Mercury Vapor At Silver Peak Area (Henkle, Et Al., 2005) | Open...
Mercury Vapor At Silver Peak Area (Henkle, Et Al., 2005) Exploration Activity Details Location Silver Peak Area Exploration Technique Mercury Vapor Activity Date Usefulness useful...
Does EIA report water vapor emissions data? - FAQ - U.S. Energy ...
U.S. Energy Information Administration (EIA)
Does EIA report water vapor emissions data? No. Water vapor is the most abundant greenhouse gas, but most scientists believe that human activity has a very small ...
EA-0881: Tank 241-c-103 Organic Vapor and Liquid Characterization...
881: Tank 241-c-103 Organic Vapor and Liquid Characterization and Supporting Activities, Hanford Site, Richland, Washington EA-0881: Tank 241-c-103 Organic Vapor and Liquid...
The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient of performance for geothermal heat pumps based on a new regenerative thermodynamic cycle as comparing to existing technology. In order to demonstrate the improved performance of the prototype, it will be compared to published parameters of commercially available geothermal heat pumps manufactured by US and foreign companies. Other objectives are to optimize the design parameters and to determine the economic viability of the new technology. Background (as stated in the proposal): The proposed technology closely relates to EERE mission by improving energy efficiency, bringing clean, reliable and affordable heating and cooling to the residential and commercial buildings and reducing greenhouse gases emission. It can provide the same amount of heating and cooling with considerably less use of electrical energy and consequently has a potential of reducing our nations dependence on foreign oil. The theoretical basis for the proposed thermodynamic cycle was previously developed and was originally called a dynamic equilibrium method. This theory considers the dynamic equations of state of the working fluid and proposes the methods for modification of T-S trajectories of adiabatic transformation by changing dynamic properties of gas, such as flow rate, speed and acceleration. The substance of this proposal is a thermodynamic cycle characterized by the regenerative use of the potential energy of two-phase flow expansion, which in traditional systems is lost in expansion valves. The essential new features of the process are: (1) The application of two-step throttling of the working fluid and two-step compression of its vapor phase. (2) Use of a compressor as the initial step compression and a jet device as a second step, where throttling and compression are combined. (3) Controlled ratio of a working fluid at the first and second step of compression. In the proposed system, the compressor compresses the vapor only to 50-60% of the final pressure, while the additional compression is provided by a jet device using internal potential energy of the working fluid flow. Therefore, the amount of mechanical energy required by a compressor is significantly reduced, resulting in the increase of efficiency (either COP or EER). The novelty of the cycle is in the equipment and in the way the multi-staging is accomplished. The anticipated result will be a new refrigeration system that requires less energy to accomplish a cooling task. The application of this technology will be for more efficient designs of: (1) Industrial chillers, (2) Refrigeration plants, (3) Heat pumps, (4) Gas Liquefaction plants, (5) Cryogenic systems.
Mark J. Bergander
Enhanced Attenuation Technologies: Passive Soil Vapor Extraction
Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE flowchart provides a structured process to determine if the technology is, or is not, reasonable and defensible for a particular site. The central basis for that decision is the expected performance of PSVE under the site specific conditions. Will PSVE have sufficient mass removal rates to reduce the release, or flux, of contamination into the underlying groundwater so that the site can meet it overall remedial objectives? The summary technical information, case study experiences, and structured decision process provided in this 'user guide' should assist environmental decision-makers, regulators, and engineers in selecting and successfully implementing PSVE at appropriate sites.
Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.
Desalination Using Vapor-Compression Distillation
The ability to produce potable water economically is the primary purpose of seawater desalination research. Reverse osmosis (RO) and multi-stage flash (MSF) cost more than potable water produced from fresh water resources. As an alternative to RO and MSF, this research investigates a high-efficiency mechanical vapor-compression distillation system that employs an improved water flow arrangement. The incoming salt concentration was 0.15% salt for brackish water and 3.5% salt for seawater, whereas the outgoing salt concentration was 1.5% and 7%, respectively. Distillation was performed at 439 K (331oF) and 722 kPa (105 psia) for both brackish water feed and seawater feed. Water costs of the various conditions were calculated for brackish water and seawater feeds using optimum conditions considered as 25 and 20 stages, respectively. For brackish water at a temperature difference of 0.96 K (1.73oF), the energy requirement is 2.0 kWh/m3 (7.53 kWh/kgal). At this condition, the estimated water cost is $0.39/m3 ($1.48/kgal) achieved with 10,000,000 gal/day distillate, 30-year bond, 5% interest rate, and $0.05/kWh electricity. For seawater at a temperature difference of 0.44 K (0.80oF), the energy requirement is 3.97 kWh/m3 (15.0 kWh/kgal) and the estimated water cost is $0.61/m3 ($2.31/kgal). Greater efficiency of the vapor compression system is achieved by connecting multiple evaporators in series, rather than the traditional parallel arrangement. The efficiency results from the gradual increase of salinity in each stage of the series arrangement in comparison to parallel. Calculations using various temperature differences between boiling brine and condensing steam show the series arrangement has the greatest improvement at lower temperature differences. The following table shows the improvement of a series flow arrangement compared to parallel: ?T (K) Improvement (%)*1.111 2.222 3.333 15.21 10.80 8.37 * Incoming salt concentration: 3.5% Outgoing salt concentration: 7% Temperature: 450 K (350oF) Pressure: 928 kPa (120 psig) Stages: 4
Lubis, Mirna R.
Numerical simulation of water injection into vapor-dominated reservoirs
Water injection into vapor-dominated reservoirs is a means of condensate disposal, as well as a reservoir management tool for enhancing energy recovery and reservoir life. We review different approaches to modeling the complex fluid and heat flow processes during injection into vapor-dominated systems. Vapor pressure lowering, grid orientation effects, and physical dispersion of injection plumes from reservoir heterogeneity are important considerations for a realistic modeling of injection effects. An example of detailed three-dimensional modeling of injection experiments at The Geysers is given.
Pruess, K.
Controlling the vapor pressure of a mercury lamp
The invention described herein discloses a method and apparatus for controlling the Hg vapor pressure within a lamp. This is done by establishing and controlling two temperature zones within the lamp. One zone is colder than the other zone. The first zone is called the cold spot. By controlling the temperature of the cold spot, the Hg vapor pressure within the lamp is controlled. Likewise, by controlling the Hg vapor pressure of the lamp, the intensity and linewidth of the radiation emitted from the lamp is controlled. 2 figs.
Grossman, M.W.; George, W.A.
The invention described herein discloses a method and apparatus for controlling the Hg vapor pressure within a lamp. This is done by establishing and controlling two temperature zones within the lamp. One zone is colder than the other zone. The first zone is called the cold spot. By controlling the temperature of the cold spot, the Hg vapor pressure within the lamp is controlled. Likewise, by controlling the Hg vapor pressure of the lamp, the intensity and linewidth of the radiation emitted from the lamp is controlled.
Grossman, Mark W. (Belmont, MA); George, William A. (Rockport, MA)
Simple microwave field imaging technique using hot atomic vapor cells
We demonstrate a simple technique for microwave field imaging using alkali atoms in a vapor cell. The microwave field to be measured drives Rabi oscillations on atomic hyperfine transitions, which are detected in a spatially resolved way using a laser beam and a CCD camera. Our vapor cell geometry enables single-shot recording of two-dimensional microwave field images with 350 {\\mu}m spatial resolution. Using microfabricated vapor cell arrays, a resolution of a few micrometers seems feasible. All vector components of the microwave magnetic field can be imaged. Our apparatus is simple and compact and does not require cryogenics or ultra-high vacuum.
B�hi, Pascal
We demonstrate a simple technique for microwave field imaging using alkali atoms in a vapor cell. The microwave field to be measured drives Rabi oscillations on atomic hyperfine transitions, which are detected in a spatially resolved way using a laser beam and a camera. Our vapor cell geometry enables single-shot recording of two-dimensional microwave field images with 350 {\\mu}m spatial resolution. Using microfabricated vapor cell arrays, a resolution of a few micrometers seems feasible. All vector components of the microwave magnetic field can be imaged. Our apparatus is simple and compact and does not require cryogenics or ultra-high vacuum.
Pascal B�hi; Philipp Treutlein
Preliminary assessment of halogenated alkanes as vapor-phase tracers
New tracers are needed to evaluate the efficiency of injection strategies in vapor-dominated environments. One group of compounds that seems to meet the requirements for vapor-phase tracing are the halogenated alkanes (HCFCs). HCFCs are generally nontoxic, and extrapolation of tabulated thermodynamic data indicate that they will be thermally stable and nonreactive in a geothermal environment. The solubilities and stabilities of these compounds, which form several homologous series, vary according to the substituent ratios of fluorine, chlorine, and hydrogen. Laboratory and field tests that will further define the suitability of HCFCs as vapor-phase tracers are under way.
Adams, Michael C.; Moore, Joseph N.; Hirtz, Paul
Mercury Vapor At Medicine Lake Area (Kooten, 1987) | Open Energy
Kooten, 1987) Kooten, 1987) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor At Medicine Lake Area (Kooten, 1987) Exploration Activity Details Location Medicine Lake Area Exploration Technique Mercury Vapor Activity Date Usefulness could be useful with more improvements DOE-funding Unknown References Gerald K. Van Kooten (1987) Geothermal Exploration Using Surface Mercury Geochemistry Retrieved from "http://en.openei.org/w/index.php?title=Mercury_Vapor_At_Medicine_Lake_Area_(Kooten,_1987)&oldid=386431" Category: Exploration Activities What links here Related changes Special pages Printable version Permanent link Browse properties 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation:
A cold cathode vacuum discharge tube, and method for making same, are disclosed with an interior surface of the trigger probe coated with carbon deposited by carbon vapor deposition (CVD) or diamond-like carbon (DLC) deposition. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging. 15 figs.
Boettcher, G.E.
A cold cathode vacuum discharge tube, and method for making same, with an interior surface of the trigger probe coated with carbon deposited by chemical vapor deposition (CVD) or diamond-like carbon (DLC) deposition are disclosed. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging. 14 figs.
Catalytic Reactor For Oxidizing Mercury Vapor
A catalytic reactor (10) for oxidizing elemental mercury contained in flue gas is provided. The catalyst reactor (10) comprises within a flue gas conduit a perforated corona discharge plate (30a, b) having a plurality of through openings (33) and a plurality of projecting corona discharge electrodes (31); a perforated electrode plate (40a, b, c) having a plurality of through openings (43) axially aligned with the through openings (33) of the perforated corona discharge plate (30a, b) displaced from and opposing the tips of the corona discharge electrodes (31); and a catalyst member (60a, b, c, d) overlaying that face of the perforated electrode plate (40a, b, c) opposing the tips of the corona discharge electrodes (31). A uniformly distributed corona discharge plasma (1000) is intermittently generated between the plurality of corona discharge electrode tips (31) and the catalyst member (60a, b, c, d) when a stream of flue gas is passed through the conduit. During those periods when corona discharge (1000) is not being generated, the catalyst molecules of the catalyst member (60a, b, c, d) adsorb mercury vapor contained in the passing flue gas. During those periods when corona discharge (1000) is being generated, ions and active radicals contained in the generated corona discharge plasma (1000) desorb the mercury from the catalyst molecules of the catalyst member (60a, b, c, d), oxidizing the mercury in virtually simultaneous manner. The desorption process regenerates and activates the catalyst member molecules.
Helfritch, Dennis J. (Baltimore, MD)
Modeling of LNG Pool Spreading and Vaporization
In this work, a source term model for estimating the rate of spreading and vaporization of LNG on land and sea is introduced. The model takes into account the composition changes of the boiling mixture, the varying thermodynamic properties due to preferential boiling within the mixture and the effect of boiling on conductive heat transfer. The heat, mass and momentum balance equations are derived for continuous and instantaneous spills and mixture thermodynamic effects are incorporated. A parameter sensitivity analysis was conducted to determine the effect of boiling heat transfer regimes, friction, thermal contact/roughness correction parameter and VLE/mixture thermodynamics on the pool spreading behavior. The aim was to provide a better understanding of these governing phenomena and their relative importance throughout the pool lifetime. The spread model was validated against available experimental data for pool spreading on concrete and sea. The model is solved using Matlab for two continuous and instantaneous spill scenarios and is validated against experimental data on cryogenic pool spreading found in literature.
Basha, Omar 1988-
Occupational Exposure Evaluation of Complex Vapor Mixtures at the Hanford Nuclear Waste Site, Washington Work-site Vapor Characterization
Extensive sampling and analysis has been done over the years to characterize the radioactive and chemical properties of hazardous waste stored in 177 underground tanks at the Hanford site in eastern Washington State. The purpose of these analyses was to evaluate safety and environmental concerns related to tank stability. More recently, characterization studies have broadened to evaluate potential health hazards of chemical vapors at the ground surface, where workers perform maintenance and waste transfer activities. Chemical vapor emissions from underground hazardous waste storage tanks on the Hanford site are a potential concern because workers enter the tank farms on a regular basis for waste retrievals, equipment maintenance, and surveillance. The extensive sampling done during this campaign evaluated vapor concentrations of more than 100 different chemical at 70 sites in and around one section of the tank farms. Sampling identified only four vapors (ammonia, nitrous oxide, nitrosodimethylamine, and nitrosomethylethylamine) that were present above occupational exposure limits. These elevated concentrations were detected only at exhaust stacks and passive breather filter outlets. Beyond five feet from the sources, vapors disperse rapidly. No vapors were measured above 10% of their OELs more than five feet from the source. This suggests that vapor controls can be focused on limited hazard zones around sources. (authors)
Anderson, T. J. [CH2M HILL Hanford Group, Inc. / Environmental Health, P.O. Box 1000, S7-70, Richland, WA 99352 (United States)
ARM - Field Campaign - Arctic Winter Water Vapor IOP
govCampaignsArctic Winter Water Vapor IOP govCampaignsArctic Winter Water Vapor IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Arctic Winter Water Vapor IOP 2004.03.09 - 2004.04.09 Lead Scientist : Ed Westwater Data Availability http://www.etl.noaa.gov/programs/2004/wviop/data will contain quicklooks of all of the data. For data sets, see below. Summary During the IOP, the Ground-based Scanning Radiometer of NOAA/ETL, and the ARM MicroWave Radiometer and Microwave Profiler, yielded excellent data over a range of conditions. In all, angular-scanned and calibrated radiometric data from 22.345 to 380 GHz were taken. The Precipitable Water Vapor varied about an order of magnitude from 1 to 10 mm, and surface temperatures varied from about -10 to -40 deg. Celcius. Vaisala RS90
Overview of the ARM/FIRE Water Vapor Experiment (AFWEX)
Overview of the ARM/FIRE Water Vapor Overview of the ARM/FIRE Water Vapor Experiment (AFWEX) D. C. Tobin, H. E. Revercomb, and D. D. Turner University of Wisconsin-Madison Madison, Wisconsin Introduction An overview of the ARM/FIRE Water Vapor Experiment (AFWEX) is given. This field experiment was conducted during November-December 2000 near the central ground-based Atmospheric Radiation Measurement (ARM) site in north central Oklahoma, and was sponsored jointly by the ARM, the National Aeronautics and Space Administration (NASA) First ISCCP Regional Experiment (FIRE), and the National Polar-orbiting Operational Environmental Satellite System (NPOESS) programs. Its primary goal was to collect accurate measurements of upper-level (~8 to 12 km) water vapor near the ground-based ARM site. These data are being used to determine the accuracy of measurements that are
Mercury Vapor At Kawaihae Area (Thomas, 1986) | Open Energy Information
Mercury Vapor At Kawaihae Area (Thomas, 1986) Mercury Vapor At Kawaihae Area (Thomas, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor At Kawaihae Area (Thomas, 1986) Exploration Activity Details Location Kawaihae Area Exploration Technique Mercury Vapor Activity Date Usefulness not useful DOE-funding Unknown Notes The soil geochemistry yielded quite complex patterns of mercury concentrations and radonemanation rates within the survey area (Cox and Cuff, 1981c). Mercury concentrations (Fig. 38) showed a general minimum along the Kawaihae-Waimea roads and a broad trend of increasing mercury concentrations toward both the north and south. There is no correlation apparent between the mercury patterns and either the resistivity sounding data or the surface geology in the area. The radon emanometry data (Fig.
Mercury Vapor At Lualualei Valley Area (Thomas, 1986) | Open Energy
Mercury Vapor At Lualualei Valley Area (Thomas, 1986) Mercury Vapor At Lualualei Valley Area (Thomas, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Mercury Vapor At Lualualei Valley Area (Thomas, 1986) Exploration Activity Details Location Lualualei Valley Area Exploration Technique Mercury Vapor Activity Date Usefulness useful DOE-funding Unknown Notes Soil mercury and radon emanation surveys were performed over much of the accessible surface of Lualualei Valley (Cox and Thomas, 1979). The results of these surveys (Figs 7 and 8) delineated several areas in which soil mercury concentrations or radon emanation rates were substantially above normal background values. Some of these areas were apparently coincident with the mapped fracture systems associated with the caldera boundaries.
Industrial Heat Pumps Using Solid/Vapor Working Fluids
Industrial heat pumps have the potential to reduce the operating costs of chemical and heat treating processes in the chemical, petroleum, paper, dairy, and many other industries. The cost development of fossil fuel and other prime energy require excellent efficiency/cost ratios and hardware designs adaptable to specific process needs, in order to compete with vapor re-compression recovery systems. The state-of-the-art heat pump equipment employing liquid/vapor working fluids fulfills the requirements only in some applications. The employment of solid/vapor complex compounds leads to more cost effective heat recovery, which is due to simple hardware with no moving parts, extraordinary low maintenance effort, excellent temperature lifts avoiding the need of two-stage systems, and low first cost. This paper describes the advantages and disadvantages of solid/vapor working media.
Rockenfeller, U.
Broadband Water Vapor Transmission Functions for Atmospheric IR Flux Computations
Transmission functions associated with water vapor molecular line and e-type absorption in the IR spectral regions are presented in the form of simple analytical functions and small tables, from which atmospheric IR fluxes and cooling rates can ...
Characterization of Advanced Avalanche Photodiodes for Water Vapor Lidar Receivers
Development of advanced differential absorption lidar (DIAL) receivers is very important to increase the accuracy of atmospheric water vapor measurements. A major component of such receivers is the optical detector. In the near-infrared wavelength range ...
Refaat Tamer F.; Halama Gary E.; DeYoung Russell J.
Advanced Chemical Heat Pumps Using Liquid-Vapor Reactions
Chemical heat pumps utilizing liquid-vapor reactions can be configured in forms analogous to electric drive vapor-compression heat pumps and heat activated absorption heat pumps. Basic thermodynamic considerations eliminate some heat pumps and place restrictive working fluid requirements on others, but two thermodynamically feasible systems have significant potential advantage over conventional technology. An electric drive reactive heat pump can use smaller heat exchangers and compressor than a vapor-compression machine, and have more flexible operating characteristics. A waste heat driven heat pump (temperature amplifier) using liquid-vapor chemical reactions- can operate with higher coefficient of performance and smaller heat exchangers than an absorption temperature amplifying heat pump. Higher temperatures and larger temperature lifts should also be possible.
Kirol, L.
Upper-Tropospheric Water Vapor from UARS MLS
Initial results of upper-tropospheric water vapor obtained from the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) are presented. MLS is less affected by clouds than infrared or visible techniques, and the UARS ...
W. G. Read; J. W. Waters; D. A. Flower; L. Froidevaux; R. F. Jarnot; D. L. Hartmann; R. S. Harwood; R. B. Rood
Intercomparison of Four Commercial Analyzers for Water Vapor Isotope Measurement
The ?18O and ?D of atmospheric water vapor are important tracers in hydrological and ecological studies. Isotope ratio infrared spectroscopy (IRIS) provides an in situ technology for measuring ?18O and ?D in ambient conditions. An intercomparison ...
Xue-Fa Wen; Xuhui Lee; Xiao-Min Sun; Jian-Lin Wang; Ya-Kun Tang; Sheng-Gong Li; Gui-Rui Yu
Moisture Vertical Structure, Column Water Vapor, and Tropical Deep Convection
The vertical structure of the relationship between water vapor and precipitation is analyzed in 5 yr of radiosonde and precipitation gauge data from the Nauru Atmospheric Radiation Measurement (ARM) site. The first vertical principal component of ...
Christopher E. Holloway; J. David Neelin
Improved Magnus Form Approximation of Saturation Vapor Pressure
Algorithms, based on Magnus's form equations, are described that minimize the difference between several relationships between temperature and water vapor pressure at saturation that are commonly used in archiving data. The work was initiated in ...
Oleg A. Alduchov; Robert E. Eskridge
Ice Growth from the Vapor at ?5�C
Results are summarized and illustrated from a long series of experiments on ice growth from the vapor, nearly all in a very small range of conditions: ?5�C, slightly below liquid water saturation, with minimal environmental gradients and no ...
Charles A. Knight
Numerical analysis of vapor flow in a micro heat pipe
The vapor flow in a flat plate micro heat pipe with both uniform and linear heat flux boundary conditions has been numerically analyzed. For both types of boundary conditions, the Navier-Stokes equations with steady incompressible two-dimensional flow were solved using the SIMPLE method. The results indicate that the pressure, shear stress, and friction factor under linear heat flux boundary conditions are considerably smoother, and hence, more closely approximate the real situation. As the heat flux increases, the pressure drop increases, but the friction factor demonstrates only a slight change for different heat flux conditions. The size and shape of the micro heat pipe vapor space was shown to have a significant influence on the vapor flow behavior for micro heat pipes. When the vapor space area decreases, the pressure drop, shear stress, and friction factor all significantly increase.
Liu, Xiaoqin
Heat transfer during film condensation of a liquid metal vapor
The object of this investigation is to resolve the discrepancy between theory and experiment for the case of heat transfer durirnfilm condensation of liquid metal vapors. Experiments by previous investigators have yielded ...
Sukhatme, S. P.
Heat transfer during film condensation of potassium vapor
The object of this work is to investigate theoretically and experimentally the following two phases of heat transfer during condensation of potassium vapore, a. Heat transfer during film condensation of pure saturated ...
Kroger, Detlev Gustav
The Arm Program's Water Vapor Intensive Observation Periods
A series of water vapor intensive observation periods (WVIOPs) were conducted at the Atmospheric Radiation Measurement (ARM) site in Oklahoma between 1996 and 2000. The goals of these WVIOPs are to characterize the accuracy of the operational ...
H. E. Revercomb; D. D. Turner; D. C. Tobin; R. O. Knuteson; W. F. Feltz; J. Barnard; J. B�senberg; S. Clough; D. Cook; R. Ferrare; J. Goldsmith; S. Gutman; R. Halthore; B. Lesht; J. Liljegren; H. Linn�; J. Michalsky; V. Morris; W. Porch; S. Richardson; B. Schmid; M. Splitt; T. Van Hove; E. Westwater; D. Whiteman
New Equations for Computing Vapor Pressure and Enhancement Factor
Equations are presented which relate saturation vapor pressure to temperature for moist air. The equations are designed to be easily implemented on a calculator or computer and can be used to convert in either direction. They are more accurate ...
Arden L. Buck
Solar Radiation Absorption due to Water Vapor: Advanced Broadband Parameterizations
Accurate parameterizations for calculating solar radiation absorption in the atmospheric column due to water vapor lines and continuum are proposed for use in broadband shortwave radiative transfer codes. The error in the absorption values is ...
Tatiana A. Tarasova; Boris A. Fomin
Water vapor and the dynamics of climate changes
Water vapor is not only Earth's dominant greenhouse gas. Through the release of latent heat when it condenses, it also plays an active role in dynamic processes that shape the global circulation of the atmosphere and thus ...
Schneider, Tapio
Column Water Vapor Content in Clear and Cloudy Skies
With radiosonde data from 15 Northern Hemisphere stations, surface-to-400-mb column water vapor is computed from daytime soundings for 1988�1990. On the basis of simultaneous surface visual cloud observations, the data are categorized according ...
Dian J. Gaffen; William P. Elliott
Raman Lidar Profiling of Tropospheric Water Vapor over Kangerlussuaq, Greenland
A new measurement capability has been implemented in the Arctic Lidar Technology (ARCLITE) system at the Sondrestrom upper-atmosphere research facility near Kangerlussuaq, Greenland (67.0�N, 50.9�W), enabling estimates of atmospheric water vapor ...
Ryan Reynolds Neely III; Jeffrey P. Thayer
Lidar Monitoring of the Water Vapor Cycle in the Troposphere
The water vapor mixing ratio distribution in the lower and middle troposphere has been continuously monitored, using an active lidar system. The methodology of the differential absorption laser method used for these measurements is summarized and ...
C. Cahen; G. Megie; P. Flamant
(Acidic deposition and the environment)
The travelers presented several papers at the Fourth International Conference on Acidic Deposition. These covered the following topics: atmospheric chemistry and deposition of airborne nitrogen compounds, soil solution chemistry in high-elevation spruce forests, and forest throughfall measurements for estimating total sulfur deposition to ecosystems. In addition, S. E. Lindberg was invited to organize and chair a conference session on Throughfall and Stemflow Experiments, and to present an invited lecture on Atmospheric Deposition and Canopy Interactions of Metals and Nitrogen in Forest Ecosystems: The Influence of Global Change'' at the 110th Anniversary Celebration of the Free University of Amsterdam.
Garten, C.T.; Lindberg, S.E.; Van Miegroet, H.
CVD Report draft1
Energy. 8,078. 8,059. 8,205. 146. 1.8%. 127. 1.6%. (Office of Science). 3,074. 3,035 ... (Energy R&D). 1,244 ..... Bob Guenther, Duke University; Leeward Bean,.
Injection locked oscillator system for pulsed metal vapor lasers
An injection locked oscillator system for pulsed metal vapor lasers is disclosed. The invention includes the combination of a seeding oscillator with an injection locked oscillator (ILO) for improving the quality, particularly the intensity, of an output laser beam pulse. The present invention includes means for matching the first seeder laser pulses from the seeding oscillator to second laser pulses of a metal vapor laser to improve the quality, and particularly the intensity, of the output laser beam pulse.
Warner, Bruce E. (Livermore, CA); Ault, Earl R. (Dublin, CA)
Determination of the Vapor Pressure of Lanthanum Fluoride
Preliminary experiments have been made to determine the vapor pressure of lanthanum fluoride between 0.001 and 0.1 millimeter of mercury by means of the Knudsen effusion method. A tantalum cell for this purpose is described. Only preliminary results were obtained and they were all in a relatively high pressure region. However, a plot of the vapor pressure against the reciprocal of absolute temperature approximates a straight line such as would be predicted from theoretical considerations.
Stone, B. D.
Heat Recovery in Distillation by Mechanical Vapor Recompression
A significant reduction in distillation tower energy requirements can be achieved by mechanical vapor recompression. Three design approaches for heating a distillation tower reboiler by mechanical vapor recompression are presented. The advantages of using a screw compressor are discussed in detail. An example of a xylene extraction tower is sited, illustrating the economic attractiveness in which a simple payback period of less than two years is achievable.
Becker, F. E.; Zakak, A. I.
c o l e P o l y t e c h n i q u e Benedict O'Donnell
silicon c-Si Crystalline Silicon CVD Chemical Vapor Deposition FF Fill factor % ITO Indium-Tin-Oxide JSC .......................................................................................... 35 4. Thin layers of tin and ITO over stable zinc oxide of energy imports led to increased funding in renewable energy. Whereas research had previously focused