Samples of vacuum-evaporated CdTe were sealed, together with a source of S vapor, into evacuated silica ampoules and were annealed (372, 450 or 550C, up to 670h). The S diffusion profiles were measured by means of secondary ion mass spectrometry. A method for correcting for finite film thickness was used to determine the grain boundary diffusion coefficients. These showed that films which were grown at high temperatures, such as those produced by close-space sublimation, could possess S enriched grain boundaries that extended through the entire thickness of the CdTe film. However, extensive decoration of the grain boundary by hexagonal CdSxTe1-x was expected to be unlikely.

Sulfur Diffusion in Cadmium Telluride Thin Films Part 1 - the Grain Boundary Diffusion Coefficient. D.W.Lane, J.D.Painter, M.A.Cousins, G.J.Conibeer, K.D.Rogers: Thin Solid Films, 2003, 431-432, 73-7