Chemical Bath Deposition of CdS Thin Films on Cuins2 and Si Substrates - A Comparative X-Ray Emission Study

Wide-gap chalcopyrite CuInS
₂
("CIS")-based thin film solar cells are far behind their low-gap counterparts in terms of photovoltaic performance. To date, most chalcopyrite-based devices include a CdS layer, which is deposited in a chemical bath (CBD). In order to shed light on the effects induced by the interface formation, the buried CdS/CIS interface was investigated by X-ray emission spectroscopy. By comparing the CdS/CIS interface with a CdS/Si reference heterostructure, we find that the properties of the substrate determine the chemical structure of the heterointerface. In particular, we find that the formation of the CBD-CdS on Si substrates is delayed compared to that on CIS absorbers