Structural and optical properties of polycrystalline CdS thin films deposited by electron beam evaporation

Highly crystalline and transparent cadmium sulphide (CdS) films were deposited on glass substrate by electron beam evaporation technique. The structural and optical properties of the films were investigated. The X-ray diffraction analysis revealed that the CdS films have a hexagonal structure and exhibit preferred orientation along the (002) plane. Meanwhile, the crystalline quality of samples increased first and then decreased as the substrate temperature improved, which is attributed to the variation in film thickness. UV-vis spectra of CdS films indicate that the absorption edge becomes steeper and the band gap present fluctuation changes in the range of 2.389–2.448eV as the substrate temperature increased. The photoluminescence peak of the CdS films was found to be broadened seriously and there only emerges a red emission band at 1.60 eV The above results were analyzed and discussed.