Structural, optical and electrical properties of CdZnS thin films

Abstract

The thin films of Cd1-x Zn x S (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) have been prepared by the vacuum evaporation method using a mechanically alloyed mixture of CdS and ZnS. The structural, optical and electrical properties have been investigated through the X-ray diffractometer, spectrophotometer and Keithley electrometer. The X-ray diffraction patterns of these films show that films are polycrystalline in nature having preferential orientation along the (002) plane. In the absorption spectra of these films, absorption edge shifts towards lower wavelength with the increase of Zn concentration. The energy band gap has been determined using these spectra. It is found that the energy band gap increases with increasing Zn concentration. The electrical conductivity of so prepared thin films has been determined using a I–V characteristic curve for these films. The result indicates that the electrical conductivity decreases with increasing Zn content and increases with temperature. An effort has also been made to obtain activation energy of these films which increases with increasing Zn concentration in CdS.