Structural and optical properties of Nanocrystalline ZnxCd1-xS thin films deposited by chemical bath technique

Abstract

Nanocrystalline zinc cadmium sulfide (ZnxCd1-xS) thin films were deposited on glass substrate by chemical bath deposition (CBD) technique using the mixed aqueous solution of zinc chloride ((ZnCl2), cadmium chloride (CdCl2), thiourea (CS(NH2)2) and ammonia solution (NH4OH). The as deposited films were characterized by X-ray diffraction (XRD), atomic force microscopic (AFM) and UV-VIS spectrophotometer techniques to reveal their structural, morphological and optical properties. The XRD analysis shows mixture of cubic and hexagonal structure and the intensity decreases with the increasing of Zn2+ content. AFM analysis of ZnxCd1-xS thin films were found to be nanocrystalline. Optical absorption measurements indicated that the band gaps of ZnxCd1-xS thin films increased from (3.63 to 3.93 eV) with increasing Zn2+ content in chemical bath from (0.1- 0.9). The band gap is found to be higher indicating blue shift with respect to the bulk value as a result of quantum size effect as expected from the nanocrystalline nature of the ZnxCd1-xS thin films.