Post-Thermal Annealing of Chemically Deposited CdS/ZnS bilayer in the preparation of CdZnS Ternary Thin Film

Abstract

Chemical bath deposition (CBD) route was employed to successfully prepare cadmium zinc sulphide (CdZnS) through CdS/ZnS bilayer and its post thermal annealing. Optical, structural as well as morphological properties of the deposited film samples were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Uv-vis spectroscopy technique, respectively. The XRD analysis revealed post thermal inter-diffusion of the two layers leading to the formation of CdZnS ternary compound with hexagonal wurtzite structure. The SEM image revealed that the grains increased as a result of annealing when compared with the as-deposited bilayer. The optical study showed a maximum percentage transmission of 70.02%, band gap energy value of 3.78 eV and Urbach energy value of 255 meV. This study revealed that the prepared CdZnS ternary compound displays properties desirable for application as buffer layer in solar cells.