Scanning electron microscopy techniques for cross-sectional analyses of thin-film solar cells

Thin-film solar cells with chalcopyrite-type absorbers such as Cu(In,Ga)Se2 or CuInS2 provide a technology with low-cost perspective at high photovoltaic performance. These solar cells generally consist of ZnO/CdS/Cu(In,Ga)Se2/Mo or ZnO/CdS/ CuInS2/Mo thin-film stacks on, e.g., glass substrates (see Figure 1). Since Cu(In,Ga)Se2 and CuInS2 are the photoactive layers in these solar cells, they are subjected to refined analyses. For research and development, it is essential to determine the influences of process parameters such as the substrate temperature during the absorber deposition or the Cu concentration within the absorber on the microstructural, compositional and electrical properties of these thin-film stacks.