electronic properties as a semiconductor (mainly electron mobility), are adversely affected by the increasing content of carbon in the alloy, presumably due to the increased disorder in the atomic network. Several studies are found in the scientific literature, mainly investigating the effects of deposition parameters on electronic quality, but practical applications of amorphous silicon carbide in commercial devices are still lacking. Properties The density of amorphous Si has been calculated as 4.90×1022 atom/cm3 (2.285 g/cm3) at 300 K. This was done using thin (5 micron) strips of amorphous silicon. This density is 1.8±0.1% less dense than crystalline Si at 300 K. Silicon is one of the few elements that expands upon cooling and has a lower density as a solid than as a liquid. Hydrogenated amorphous silicon Unhydrogenated a-Si has a very high defect density which leads to undesirable semiconductor properties such as poor photoconductivity and prevents doping which is critical to engineering semiconductor properties. By introducing hydrogen during the fabrication of amorphous silicon, photoconductivity is significantly improved and doping is made possible. Hydrogenated amorphous silicon, a-Si:H, was first fabricated in 1969 by Chittick, Alexander and Sterling by deposition using a silane gas (SiH4) precursor. The resulting material showed a lower defect density and increased conductivity due to impurities. Interest in a-Si:H came when (in 1975), LeComber and Spear discovered the ability for substitutional doping of a-Si:H using phosphine (n-type) or diborane (p-type). The role of hydrogen in reducing defects was verified by Paul's group at Harvard who found a hydrogen concentration of about 10 atomic % through IR vibration, which for Si-H bonds has a frequency of about 2000 cm−1. Starting in the 1970s, a-Si:H was developed in solar cells by David E. Carlson and C. R. Wronski at RCA Laboratories. Conversion efficiency steadily climbed to about 13.6% in 2015. Deposition processes Applications While a-Si suffers from lower electronic performance compared to c-Si, it is much more flexible in its applications. For example, a-Si layers can be made thinner than c-Si, which may produce savings on silicon material cost. One further advantage is that a-Si can be deposited at very low temperatures, e.g., as low as 75 degrees Celsius. This allows deposition on not only glass, but plastic as well, making it a candidate for a roll-to-roll processing technique. Once deposited, a-Si can be doped in a fashion similar to c-Si, to form p-type or n-type layers and ultimately