Cd Cl 2 treatment, S diffusion, and recombination in polycrystalline CdTe

Time-resolved photoluminescence measurements on glass∕SnO2∕CdTe and glass∕SnO2∕CdTe∕CdS structures indicate that the CdCl2 process, without any S present, significantly reduces recombination. However, S diffusion is required for lifetimes comparable to those observed in high-efficiency solar cells. Low-temperature photoluminescence, cathodoluminescence, and scanning electron images indicate how defect chemistry, grain-boundary passivation, and morphology are affected by S diffusion and the CdCl2 treatment.