A photoluminescence and structural analysis of CuInS2-on-Cu-tape solar cells (CISCuT)

The CISCuT (copper indium sulphide on Cu-tape) technology is a relatively new method for the production of polycrystalline thin film solar cells based on CuInS2. SEM surface images and cross sections of the CISCuT samples were taken. We used X-ray diffraction and X-ray photoelectron spectroscopy in combination with sputter depth profiling to examine the structure of the layers. Both techniques indicate the CIS layers consist of a single CuInS2 phase. In a second part, we report for the first time on the luminescent properties of the layers created by this CISCuT process. Several PL bands were detected at 1.514, 1.48, 1.39, 1.36, 1.33 eV and a broad emission from 1.25 to 0.8 eV. The layers show both excitonic emission as well as transitions related to deeper defects. Temperature dependent and excitation power dependent PL measurements were performed.