Interface properties of HCF2Cl annealed CdTe thin films for solar cells applications

CdTe thin films deposited on CdS/ZnO/ITO/glass by Closed Space Sublimation, before and after annealing in HCF2Cl (Freon gas) were etched in Bromine methanol solution for several minutes. This procedure makes the whole thickness of the CdTe layer accessible for investigation. The possible diffusion of impurities from the annealing gas, Cl or F in particular, into the CdTe thin film has been studied by means of SEM-cathodoluminescence as well as the distribution of the CL emissions within the CdTe grains. The electrical properties of the cells, determined by I-V measurements in the dark and under illumination have been correlated to the microscopic observation.