Influence of Sb addition on the structural and optical characteristics of thermally vacuum evaporated SbXSe1-x thin films

Binary chalcogenide glasses of SbXSe1-x (0.1, 0.2 and 0.3) were synthesized by the conventional melt quenching technique. Thin films of these glasses were deposited by vacuum evaporation technique. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that, the deposited films have amorphous nature. The optical properties were studied in the wavelength range 200-2500 nm by using Swanepoel method, which is based on the presence of interference fringes. Type of transition in the films is found to be indirect allowed with a value of energy gap decrease with increasing Sb-content due to the increasing of concentration of the localized states. Optical absorption parameters such as Urbach energy, skin depth, steepness, electron-phonon interaction were determined and showed composition dependence. The obtained indirect optical energy gap was found to decrease with increasing Sb-content due to the increasing of concentration of the localized states. In addition, the results indicate that the values of refractive index gradually increase with increasing Sb content which is related. The dispersion characteristics were discussed in terms of the single oscillator expressed by Wemple Di-Domenico (WD). The obtained dispersion parameters were extracted and showed compositional dependence. (C) 2016 Elsevier B.V. All rights reserved.