Abstract
► CdS thin films were prepared using thermal evaporation technique. ► The morphology of films was investigated by atomic force microscopy (AFM). ► Optical properties were investigated applying Raman and far-infrared spectroscopy. ► Numerical model for the reflectivity coefficient which includes films and substrate. ► Existence of surface optical phonon modes.
The properties of CdS thin films were investigated by applying atomic force microscopy (AFM), Raman and far-infrared spectroscopy. CdS thin films were prepared by using the thermal evaporation technique under base pressure 2×10−5torr. The quality of these films was investigated by AFM spectroscopy. We applied Raman scattering and far-infrared spectroscopy to investigate the optical properties of CdS thin films, and reveal the existence of Surface Optical Phonon (SOP) mode at 297cm−1. Effective permittivity of mixture was modeled by Maxwell–Garnet approximation. In the analysis of the far-infrared reflection spectra, a numerical model for calculating the reflectivity coefficient for a system which includes films and substrate was applied.