Effect of annealing temperature on the optical characteristics of Se80Te15Ge5 films for opto-electronic applications

Abstract

An evaporation process was used to deposit Se80Te15Ge5 thin films. The annealed films are amorphous below 373 K and polycrystalline above 423 K, according to X-ray diffraction measurements. Optical constants for these films were calculated at 323,373 and 423 K annealing temperatures. The single oscillator model is used to investigate the refractive index. The nonlinear refractive index and third-order nonlinear susceptibility are calculated. The absorbance coefficient was computed, revealing an indirect optical band gap value that decreases with annealing temperature. This decreases as the annealing temperature rises.