Raman scattering and XRD analysis in argon ion implanted CdS thin films prepared by vacuum evaporation

Abstract

CdS thin films prepared by vacuum evaporation at a substrate temperature of 423 K were implanted with a mass analysed beam of 140 keV Ar + for various doses ranging from 10 15 to 10 17 ions/cm 2. XRD pattern of the as-deposited film shows hexagonal structure with a preferred orientation along the (0 0 2) plane. Formation of metallic cadmium clusters were observed in the implanted films from the XRD patterns. Raman scattering due to the A 1(LO) phonon was observed at 299 cm −1 in the as-deposited CdS film with a large full width at half maximum (FWHM). The Raman peak position did not change much with the implantation dose. FWHM increased on implantation at low dose due to increased lattice damage and decreased at higher doses due to implantation induced annealing effect. The area under the Raman peak was found to be constant at the low dose and to increase at the higher dose, probably due to implantation induced surface roughness. The size of the Cd clusters formed in the implanted films was determined using low frequency Raman scattering (LFRS) measurements and compared with the size estimated from the XRD peak width.