Thermal effects on structural characterization of evaporated CdTe films during and after deposition

CdTe films were thermally deposited onto amorphous substrates at different temperatures (25–250°C). Post-annealing under vacuum at 300°C for 2 h has been also carried out. Using X-ray diffraction, the structural characteristics (preferential orientation, stoichiometry, microstructural properties) have been studied. Due to the high degree of preferred orientation, Voigt analysis of single reflection was used to determine the microstructural properties (crystallite size and microstrain). Raising the substrate temperature was observed to lead to a decrease in both integrated intensity and degree of preferred orientation as well as an increase in crystallite size and internal microstrain associated with improving the film stoichiometry. Post-annealing was found to increase the integrated intensity, the crystallite size and the degree of preferred orientation. On the other hand, it resulted in a decrease of FWHM and microstrain. The relative change in such parameters decreases as the film thickness increased with a pronounced change in thinner films.