Photo-electrochemical properties of flash evaporated cadmium sulphide films

Abstract

Cadmium sulphide(CdS) thin films were deposited by the flash evaporation technique using the CdS powder synthesized by a chemical precipitation method in the laboratory from AR grade cadmium acetate and thiourea. The synthesized powder was characterized by x-ray diffraction technique. Peaks corresponding to single phase hexagonal CdS were observed. This powder was used as source material for the deposition of thin films on glass and titanium substrates by the flash evaporation technique. The substrate temperature was varied in the range of 30 - 250C XRD pattern indicated that the films were polycrystalline exhibiting peaks corresponding to the hexagonal phase. Optical absorption studies indicated a direct band gap of 2.39 eV. Photo-electrochemical measurements were made on the films deposited at different substrate temperatures. The as deposited films exhibited weak photo-activity, due to the annealing in argon atmosphere.