Thin-film amorphous Silicon (a-Si) solar cells are gaining momentum in the market place.  Amorphous Silicon cells use layers of a-Si only a few micrometers thick, attached to an inexpensive backing such as glass, flexible plastic, or stainless steel.  This means that they use less than 1% of the raw material (silicon) compared standard crystalline Silicon (c-Si) cells, leading to a significant cost saving.  Production of these cells is therefore less subject to the high prices of silicon caused by recent shortages.  The flexible backing allows them to be formed to fit applications, allows for the bending inherent when used in building materials, such as roofing, and prevents breakage during shipping and handling at the installation site.

Amorphous solar cells absorbs light more efficiently than c-Si, but they do not convert sunlight quite as efficiently, they require considerably less energy to produce, and are superior to crystalline cells in terms of the time required to recover the energy cost of manufacture.  Amorphous materials, by definition, lack a crystalline structure and can be created by melting and then rapid cooling a crystalline substance as is done with a plasma vapor deposition process.

Amorphous silicon is gradually degraded, by exposure to light, by a phenomena called the Staebler-Wronski Effect (SWE).  SWE effects the power output of a-Si modules by as much as 10%. This light induced degradation is reduced by depositing the layers of the cell using high hydrogen dilution and by making combinations (alloys) of different types of cells.  Because of SWE, a-Si cells are rated in the stabilized condition, which occurs after about 100 hours exposure to light.