Light scattering and trapping in different thin film photovoltaic device
Light trapping in different thin film technologies is investigated in the context of the European integrated project ATHLET since it allows for thinner devices and thus for reduction of costs for absorber material preparation as well as for advanced multi-junction solar cells. In silicon technology, rough interfaces are typically introduced by roughening of substrates, transparent conducting oxides (TCOs) and/or reflectors at the back side to scatter the light into the absorber material. Well known rough TCOs, plasma-textured poly-Si as well as rough Cu(In,Ga)Se2 (CIGS) absorbers are used as source for light scattering in microcrystalline silicon solar cells and compared regarding their surface roughness. The results prove that CIGS and poly silicon solar cells provide efficient light scattering by the surface features of the rough absorber.