Characterization of copper-doped sprayed ZnS thin films

Zinc sulfide (ZnS) thin films were deposited on a glass substrate by the spray pyrolysis technique. The films were doped with copper using the direct method, consisting in addition of a copper salt (CuCl2) to the spray solution of ZnS. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermoluminescence (TL). XRD as well as SEM techniques have been employed to investigate the structure and surface morphology of as-deposited and doped films. Optical properties, such as transmission and the band gap have been analyzed. A drastic change in the resistivity has been observed due to the incorporation of Cu dopant and the results are discussed in detail. The effect of the spraying time on the electrical and optical properties of the films has been studied.