Structural and optical studies of nanocrystallined CdS

Abstract

CdS nanocrystalline thin films have been prepared by sol-gel spin coating method. CdS nanoparticle thin films have been prepared using cadmium nitrate as cadmium source and thiourea as sulfur source. The effect of annealing on the properties of the prepared CdS nanocrystalline films has been studied.  The x-ray diffraction studies indicated the formation of nanocrystalline CdS thin films with hexagonal phase. The grain size has been found to lie in the range of 5 to 8.2 nm depending on the annealing temperature suggesting the formation of CdS quantum dots. These results have been confirmed using high resolution transmission electron microscope (HRTEM) analysis which also indicated the formation of nanocrystalline CdS with a grain size of nearly 5 nm. The absorption spectra demonstrated the presence of quantum confinement effect in the prepared CdS nanocrystalline films because of the small size of the particles. The photoluminescence spectra of the CdS films exhibited green and yellow emission bands.