Amorphous (a-Si) and microcrystalline (µc-Si) thin film silicon solar cells are cost efficient alternatives to conventional c-Si wafer based solar modules. Relevant to the market are thin film silicon single, tandem and triple junction cells. A transparent conductive oxide (TCO) film is deposited on a substrate of glass, metal, or polymer by sputtering or by low pressure chemical vapor deposition (LPCVD). The amorphous and micro-crystalline silicon films are vapor-deposited in sequence. Here, the most commonly used method is plasma-enhanced chemical vapor deposition (PECVD). Finally, a further TCO film is applied. ###HIDE###
Stacks of amorphous/microcrystalline (a-Si/µc-Si) silicon absorbers are suitable to act as tandem cells, since the different band gaps facilitate an enhanced utilization of solar radiation. This stacking is done using the same technologies as applied for single cells. Due to the very high spectral acceptance, amorphous/microcrystalline silicon cells have the highest efficiency potential in the area of silicon-based thin-film photovoltaic.
Metrology for PV applications