Amorphous Silicon Material
Amorphous silicon (a-Si) is the non-crystalline allotropic form of silicon. Silicon is a four-fold coordinated atom that is normally tetrahedrally bonded to four neighboring silicon atoms. In crystalline silicon this tetrahedral structure is continued over a large range, forming a well-ordered lattice (crystal).
Amorphous Silicon Solar Cells
Some of the advantages of an amorphous silicon solar cell are that they have high absorption coefficient so that you do not need a lot of material to do absorb sunlight. It is a lot cheaper than the glass, metal or plastic that you deposit it on. And it also has an excellent ecological balance sheet. Although many good things come from this, there is also some down falls to amorphous silicon solar cells. They are instable because it will generate defects states when the light hits the material. It is only 7-10% efficient when moderately stabilized.[1]