Band offsets at the ZnSe / CuInS 2 interface

ZnSe has been shown to be a promising alternative buffer in CuInS2 thin film solar cells. Here we present for the first time photoemission measurements to determine the band alignment at the ZnSe/CuInS2 interface. Epitaxial CuInS2 is used as a substrate. ZnSe is deposited in varying thicknesses by MOCVD. X-ray photoelectron spectra are measured with an Mg laboratory source and with synchrotron radiation. A valence band offset of 0.4+/-0.1eV is obtained.