Effect of heat treatments and window layer processing on the characteristics of CuInGaSe/sub 2/ thin film solar cells

Interaction between chemical bath deposited CdS and ZnO window layers are a focus of this paper. Low temperature anneals were used to follow the changes at the interface. Optical absorption spectra show that CdS and ZnO intermix upon annealing. Heat treatments applied to ZnO/CdS/CuInGaSe/sub 2/ thin film solar cells produced changes in the short and long wavelength responses. The latter is attributed to an increase in the energy gap of the absorber by diffusion of S, and it is confirmed by SIMS. The interdiffusion is shown to increase the short wavelength collection, and hence the current density of the devices. Photoluminescence data provides some indication of the quality of the interface.