Effects of pH Value on Performance of CdS Films with Chemical Bath Deposition

Abstract

CdS thin films were prepared by chemical-bath deposition (CBD) from a bath containing thiourea, acetic cadmium, ammonia and ammonium acetate in aqueous solution onto glass substrates at 80°C with stirring. The influence of pH value on the surface morphology and optical properties of the CdS thin films was investigated. Step height measurement instrument, scanning electron microscopy (SEM), X-ray diffraction (XRD), spectrophotometer and digital four-point probe resistance measurement were used to characterize their thickness, surface morphology, crystal structure, electrical and optical properties. Uniform CdS thin films were obtained when pH=11.6. There are obvious diffraction peaks at 26.04° when pH is 11.6. The transmittance increases as the pH values increase. The experiment show that pH value play a vital role in the properties of the CdS thin films.