Effect of annealing temperature on the optical properties of spin coated CdS/PVA thin films

CdS thin films have been prepared using cadmium nitrate (mw=308.47 and 0.6 M) as cadmium source and thiourea (M.Wt=76.12 and 1 M) as sulfur source and polyvinyl alcohol (PVA) as a matrix. Thin films are deposited on glass substrate using spin coating technique. The measured sample thickness was 67.7 mu m. The effect of annealing temperatures (100 degrees, 150 degrees and 200 degrees C)on the structural and optical properties of CdS thin films has been investigated. The surface morphology has been studied by AFM and also by X-ray technique. The results show that the grain size of the sample increases with increase in annealing temperature. The absorption coefficient, refractive index, extinction coefficient and dielectric constant increase with increasing of annealing temperature while the transmission and energy gap decrease with increase of annealing temperature.