A method was presented for the analysis of the diffusion, of CdS into CdTe thin films, using X-ray diffraction. This permitted both bulk and grain-boundary diffusion coefficients to be estimated. The equilibrium phase diagrams for the CdTeS and CdSTe alloy systems were determined for 625 to 415C. The measured diffraction line profiles for the time-progressive diffusion of CdS into CdTe films, resulting from heat-treatment at 440C, were modelled by using bulk and grain-boundary diffusion coefficients of 1.25 x 10-13 (figure 27) and 1.5 x 10-8cm2/s, respectively. The modelling of diffraction-line profiles for samples which were treated at 380 to 480C yielded Arrhenius activation energies, for bulk and grain-boundary diffusion, of 2.8 and 2.0eV respectively. The bulk diffusion coefficients which were obtained by using thin-film structures were comparable to those deduced, from Auger depth-profiles for CdS/CdTe couples, by using CdTe single crystals.

Interdiffusion of CdS/CdTe Thin Films: Modelling X-Ray Diffraction Line Profiles. B.E.McCandless, M.G.Engelmann, R.W.Birkmire: Journal of Applied Physics, 2001, 89[2], 988-94