CdCl₂-treated CdTe thin films deposited by the close spaced sublimation technique

Cadmium telluride thin films were prepared by the close spaced sublimation (CSS) technique, using CdTe powder as evaporant and were submitted to a chemical treatment at 25°C in a saturated CdCl₂ solution (2.08 g/100 mL methanol), followed by heat treatment under vacuum ~10⁻³ mbar at 400°C for 30 min. The effect of chemical and thermal treatments on the crystallographic, morphological, optical, and electrical properties were studied through XRD, scanning electron microscope (SEM), spectrophotometry, and dc electrical resistivity measurements, respectively. The studies revealed that the CdTe grows in face centered cubic phase and that post-deposition treatment affects the morphology as well as the crystallographic properties. The effect on the morphology is stronger. Increase of the grain size was observed in the samples treated thermally. The electrical resistivity drops by a factor of 20 in CdCl₂-immersed and heated samples.