INFLUENCE OF SUBSTRATE TEMPERATURE ON THE STRUCTURAL AND OPTICAL PROPERTIES OF CdS THIN FILMS

Abstract

CdS thin films were deposited on glass substrates at different temperatures by chemical spray pyrolysis. The prepared films were characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and UV-Visible spectrophotometer. X-ray diffraction study shows a phase transition from cubic to hexagonal phase with the increase in substrate temperature from 200 °C to 400 °C and improves the crystalline of films. AFM analysis shows that the root mean square (RMS) surface roughness ranges from 15 nm for 200 °C films to 24.9 nm for 400 °C films. Optical characterization indicates that deposited film by chemical spray pyrolysis at different temperatures has a small decrease in band gap, which can be related to a phase change from cubic to hexagonal phase.