First Principles assisted modeling to understand Chlorine passivation of CdTe grain boundary

Abstract

A computational study on cadmium telluride (CdTe) (111)/(220) grain boundary was performed using a first-principles approach. Cadmium chloride (CdCl2) treatment of CdTe based solar cells has proven to be highly beneficial for device performance. Published literature suggests incorporation of chlorine at Te site (ClTe) in CdTe grain boundaries. Density Functional Theory was therefore used to identify the mechanisms responsible for enhancing CdTe device performance after CdCl2 treatment. The computational model explains the formation of local p-n-p junctions through field effect passivation after inclusion of ClTe, which significantly improves CdTe device performance by mitigating recombination at the interface.