ELECTRICAL AND OPTICAL CHARACTERIZATION OF METAL SULPHIDE THIN FILMS USING CHEMICAL BATH DEPOSITION TECHNIQUE

Abstract

Semiconducting lead sulphide (PbS) and zinc sulphide (ZnS) thin films were deposited on glass substrate using relatively simple Chemical Bath Deposition technique (CBD). Optical characterization of the films shows that both materials were transparent to visible light, opaque to ultraviolet radiation and near infra red radiation. The study also revealed that the electrical conductivity is inversely proportional to wavelength while optical conductivity increases with wavelength for both ZnS and PbS materials. The XRD analysis showed that the PbS materials had the 111 preferred orientation at a peak of 25.450 while the ZnS had distinct peaks at 31.59, 32.21, 44.76 and 46.730 respectively with 101, 110 and 111 preferred orientations. The energy band gap of PbS was found to be between 1.60 – 3.60 eV while that of ZnS was found to be between 3.20 – 3.70 eV. These properties make PbS and ZnS thin film find useful applications as cover plates for solar energy panels and materials in the fabrication of semiconductor devices.