Effects on the linear and nonlinear optical properties of Se-S-Sb chalcogenide glass thin films

Different composition of Se80-xS20Sbx (x=0, 2.5, 5, 7.5, 10) thin film were prepared by thermal evaporation techniques at room temperature. The amorphous crystalline nature of the investigated films was confirmed by X-ray Diffraction technique. Optical properties were calculated over a wide wavelength (500–2500 nm) using spectrophotometric measurements of transmittance and reflectance. The optical constants (n, k) for thickness (d) of the samples were analysis from optical transmittance data using the Swanepoel method. It was found that refractive index increases with increasing Sb content in Se80-xS20Sbx thin films while the optical band gap energy decreases as the Sb content increases. In terms of the Wemple–DiDomenico single-oscillator model the dispersion of the refractive index is calculated from the result of refractive index. The oscillator parameters such as the single-oscillator energy Eo, the dispersion energy Ed, the static refractive index n (0), high frequency dielectric constant (ε∞), the optical and the electrical conductivities have been estimated and it found to be Sb content dependent. From the values of the dielectric constants, the energy loss factor and energy loss functions have been analyzed. Also, the nonlinear refractive index has been investigated according to Tichy- Ticha and Fournier- Snitzer models