Investigations on nitrogen ion implantation effects in vacuum evaporated CdS thin films using Raman scattering and X-ray diffraction studies

Cadmium sulphide thin films were prepared by vacuum evaporation onto glass substrates kept at 423 K. X-ray diffraction studies revealed that the as-deposited CdS thin films have a hexagonal structure with preferential (002) orientation. Raman peak of the as-deposited film appeared at 299 cm(-1) which arised due to A(1)(LO) phonon of CdS. These films were irradiated with 100 keV nitrogen ions to various doses from 10(15) to 10(17)ions/cm(2). Formation of cadmium clusters was observed in the implanted films from the XRD patterns. Using low frequency Raman scattering measurements, the size of the cadmium clusters formed in the implanted films was estimated. A decrease in the area of Raman peak of CdS A I (LO) mode is seen on implantation. The Raman peak position did not change much whereas the FWHM increased with the ion dose. These are attributed to the effect of implantation induced lattice damage. (C) 2001 Elsevier Science B.V. All rights reserved.