STUDIES ON NEW CHEMICALLY DEPOSITED PHOTOCONDUCTING ANTIMONY TRISULFIDE THIN-FILMS

A new room temperature chemical deposition technique has been developed to deposit semiconducting antimony trisulphide thin films on conducting and ordinary glass substrates. The method is based on aqueous ammonia bath containing potassium antimonyl tartarate (PAT), triethanolamine (TEA) and thioacetamide (TAM). It has been found that the proper control of deposition bath compositions significantly influences the quality and the thickness of the Sb2S3 films. Moreover, addition of a small amount (10(-5) M) of silicotungstic acid (STA) in the deposition bath enhanced the rate of deposition and improves significantly the photoactivity of the films. The deposited films were characterized by X-ray, SEM and neutronic activation analysis. The effect of the annealing and STA on the change of the optical bandgap (E(g)) of the films was determined at 300 K. The influence of the STA on the resistivity, carrier concentrations and mobility of the films was determined by the resistivity and Hall effect measurements on the annealed samples. A very small (almost-equal-to 5%) change in the electrical resistivity has been observed for the films in which STA is incorporated. X-ray photoelectron spectroscopic (XPS) studies were carried out to determine the surface and the bulk compositions of the films. The photoconductivity studies revealed that the deposited films were highly photoconducting in nature.