Direct evidence of current blocking by ZnSe in Cu2ZnSnSe4 solar cells

Thin films of polycrystalline Cu2ZnSnSe4 were made by selenization of co-sputtered metallic precursors and processed to solar cells. Electron beam induced current (EBIC) in combination with microscopic scale IV characterization is used to investigate lateral inhomogeneities in electrical performance across the solar cell area. Transmission electron microscopy relates areas with low EBIC response to the formation of a ZnSe phase at the absorber...