Comparison of the Structural Electrical and Optical Properties of CdS Films Deposited by Chemical Bath Deposition and Spray Pyrolysis

Cadmium sulphide (CdS) thin films were obtained by two methods: chemical bath deposition (CBD) and spray pyrolysis (SP). The influence of the preparation technique on the structural, electrical and optical properties of the polycrystalline CdS films was investigated using X-ray diffraction (XRD), Van der Pauw method and optical transmission. During the CBD process, the bath was maintained heated at 70, 75 and 80 oC. For the spray deposition, cadmium chloride(CdCl2·6H2O) was chosen as a precursor and the glass substrates were heated to 250, 275 and 300 oC. The X-ray diffraction diagrams revealed that all films were crystallized in the hexagonal CdS phase with the expected values of the lattice parameters. However, the orientation and the size of the grains depend on the deposition method. The films are oriented along (002) plane in the case of spray, while they are oriented in (002) and (101) planes in the case of CBD.