Influence of Post-Deposition Treatment on the Physical Properties of CdTe Films Deposited by Stacked Elemental Layer Processing

Cadmium telluride thin films have been deposited on glass and glass/SnO₂/CdS substrates using the stacked elemental layer (SEL) technique. After the films were deposited, they were subjected to the conventional heat treatment in the presence of a CdCl₂/methanol solution. The samples were analyzed, before and after treatment, by X-ray diffraction, atomic force microscopy, cathodoluminescence and energy dispersive X-ray spectrometry. The results suggest that the treatment promotes grain growth, decreases defect concentration, and gives rise to the formation of a CdTe_1-xS_x solid solution, which replaces the CdTe original layer. The existence of this solid solution was evidenced by a reduction in the lattice parameter relative to untreated samples and confirmed by EDS analysis of treated and untreated glass/SnO₂/CdS/CdTe structures.