Studies on ZnCdSe thin films prepared by thermal evaporation

Zinc cadmium selenide (ZCS) thin films were prepared onto thoroughly cleaned glass substrates by co-evaporating high-pure zinc (Zn) and cadmium selenide (CdSe) powders and the films were subsequently annealed at 100°C for 1 h in vacuum. The influence of Zn concentration on the structural, morphological, compositional and optical properties of ZCS films was studied using X-ray diffraction (XRD), field-emission scanning electron microscopy, energy-dispersive X-ray analysis and ultraviolet–visible spectroscopy, respectively. The XRD patterns confirmed the polycrystalline nature of the ZCS films. The optical band gap of the films increased from 2·07 to 2·69 eV with increasing Zn concentration, due to the replacement of Cd with Zn atoms. The increase in optical band gap with increasing Zn concentration signifies wide coverage over the electromagnetic spectrum, which allows ZCS thin films in the application areas of optoelectronic devices.