Photoluminescence imaging analysis of doping in thin film CdS and CdS/CdTe devices

The use of photoluminescence (PL) imaging analysis to assess the effectiveness of the passivation treatment due to the presence of chlorine in CdS thin films has been investigated. In this work, we show that the chlorine doping effect in the CdS window layer can be detected by PL imaging analysis, due to the formation of a defect complex of sulfur vacancy and ClS (VS-ClS) and complexes between halogen ions and cadmium vacancies (VCd-ClS). CdTe devices with differently doped CdS layers were investigated. PL imaging, TEM, IV performance indicators and EQE analysis were performed to understand the effect of the different dopants on the electrical performances of CdTe devices.