Impurity elements such as chlorine and sulphur can have significant effects on the electrical performance of cadmium telluride (CdTe) solar cells. Here, the 3D distribution of such elements in a cadmium chloride treated CdTe device has been determined by high resolution dynamic SIMS, a novel technique that has not been applied to thin-film PV cells. It is found that as well as segregating to grain boundaries following treatment, chlorine also segregates to the CdS/CdTe interface.
Conversely, sulphur shows a U-shaped diffusion profile. These results have potential implications for the processing thin-film CdTe devices