Optical optimization of a-Si:H solar cells using planar junctions and diffuse rear reflectors

Simple unoptimized planar junction amorphous silicon-based solar cells with TiO/sub 2/ based diffuse rear reflectors can obtain i-layer absorption similar to that of solar cells prepared on high quality commercially available textured TCO substrates. Also, the naturally occurring surface roughness in amorphous and microcrystalline materials can be exploited to fabricate very effective diffuse rear reflectors. Accurate determination of surface roughness and film optical properties are required to fully probe the potential of diffuse reflection from naturally occurring surface roughness. However, the coupling of bulk optical parameters with surface roughness artifacts poses difficulties for accurate determination of film optical properties. A new technique was developed and implemented to characterize surface scattering.