Amorphous silicon (a-Si) is the non-crystalline form of silicon used for solar cells and thin-film transistors in LCDs. Used as semiconductor material for a-Si solar cells, or thin-film silicon solar cells, it is deposited in thin films onto a variety of flexible substrates, such as glass, metal and plastic. Amorphous silicon cells generally feature low efficiency. As a second-generatio. Silicon is a fourfold coordinated atom that is normally bonded to four neighboring silicon atoms. In crystalline silicon (c-Si) this tetrahedral structure continues over a large range, thus forming a well-ordered cr. Amorphous of silicon and carbon (amorphous silicon, also hydrogenated, a-Si1−xCx:H) are an interesting variant. Introduction of carbon atoms adds extra degrees of freedom for control of the pro. The density of ion implanted amorphous Si has been calculated as 4.90×10 atom/cm (2.285 g/cm ) 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 S.
