Investigation of optical, structural, and electrical properties of semiconducting films produced by different chemical techniques

In this study, the semiconducting CdS and ZnS thin films were obtained by the two methods: chemical bath deposition and spray pyrolysis under different deposition conditions. The influence of the preparation technique on the structural, electrical and optical properties of the polycrystalline CdS and ZnS films were investigated by using X-ray diffraction (XRD), Van der Pauw method and optical transmission. The optical properties of the films were investigated from optical absorption coefficient and transmittance spectra data using double beam visible spectrophotometer. By using these data the band gap energies of all films were determined. In addition, the crystal structures of all films were studied by x-ray diffraction peaks.CdxZn1-xS films were obtained with incorporation of Cd element into ZnS at different concentrations (0?x?1) by spray pyrolysis technique using aqueous solutions of CdCl2, ZnCl2 and (CS(NH)2)2, which were atomized with compressed air as carrier gas. The CdxZn1-xS films were obtained on glass substrates at different substrate temperatures. The influence of x composition on structural, optical, thermoluminescence and electrical properties of sprayed and chemical bath deposited cadmium zinc sulfide (CdZnS) films were investigated. The structural properties were determined by XRD and a hexagonal wurtzide phase was present in all as-grown samples. The films have a direct band gap which varies from 3.50 eV for zinc sulphide to 2.40 for cadmium sulphide. It was seen that the crystallinity level of the films increased with increasing x composition and grain size.Keywords: Spray Pyrolysis, Chemical Bath Deposition, Structural Properties, Optical Properties, Electrical Properties, CdS films, ZnS films, CdZnS films