Photoluminescence and photoluminescence excitation studies on CuInSe/sub 2/ absorber layers for solar cells

Abstract
We perform a systematic photoluminescence (PL) study on CuInSe/sub 2/ solar cell absorber layers. In particular, we investigate Cu/In-ratios from 1.47 to 0.46 which show that the PL response is strongly correlated to the composition. Detailed information about origin and distribution of various defect levels is obtained. Additionally, the influence of sodium diffusion from the substrate on the optical response is investigated.