Influence of CdCl2 treatment on structural and optical properties of vacuum evaporated CdTe thin films

In this article we have discussed the structural, optical properties of vacuum evaporated CdTe thin films before and after CdCl2 treatment. The CdTe thin films were prepared by vacuum evaporation. Films were prepared under the vacuum of 10(-6) Torr. The structural studies have been performed by the X-ray diffraction (XRD) technique. The XRD analysis of vacuum evaporated CdTe films reveals that the structure of films is polycrystalline in nature. However, the crystallinity has been improved after the CdCl2, treatment as shown by an increase of the diffraction peak intensities. This is due to the enhancement in the atomic mobility of CdTe. The optical properties of the CdTe thin films have been studied by the spectrophotometer in the 300-800 nm wavelength range. It is observed that the optical band gap energy is highly dependent on CdCl2, treatments. The optical transitions in these films are found to be direct and allowed. (c) 2005 Elsevier B.V. All rights reserved.