Structural and optical properties of CdS thin ®lms

CdS thin ®lms are deposited onto glass substrates by vacuum evaporation at 373 K and the ®lms are annealed at different temperatures. Rutherford backscattering spectrometry (RBS) and X-ray diffraction techniques are used to determine the thickness, composition, crystalline structure and grain size of the ®lms. The ®lms show a predominant hexagonal phase with small crystallites. The optical band gap of the ®lms are estimated using the optical transmittance measurements. A decrease in the band gap is observed for the annealed ®lms. The Raman peak position of the CdS A1 (LO) mode did not change much whereas, the full width at half maximum (FWHM) is found to decrease with annealing. # 2001 Elsevier Science B.V. All rights reserved.