Effect of pH on the Optical Properties of Cadmium Sulphide (CdS) Thin Film Deposited Using Chemical Bath Method

摘要

Cadmium Sulphide (CdS) thin films have been deposited on glass substrates at room temperature by using Chemical bath deposition method. The bath composition included cadmium chloride hemidihydrate [CdCl2.2½H2O], thiourea [SC (NH2)2] and Ammonia (NH3) solution. The effects of the pH value on the optical properties of the films have been investigated. The as-deposited films have been characterized by the UV-VIS Spectrophotometer. The spectrum showed that absorbance was high in the UV and low in the VIS-NIR region. The optimum percentage transmittance and reflectance are 84.7% and 20.3% respectively within the same region. The band gap values of the films range from 2.4 to 2.6 eV. The optical properties of the films within the UV- VIS-NIR regions indicate that the films can find application in solar thermal technology, particularly in antireflection coating.