Dispersion Parameters and Optical Band Gap in Se_(80.5)Bi_(1.5)Te_(18-y)Sb_y Amorphous Thin Films

摘要

The dispersion parameters such as single-oscillator energy (E_0), dispersive energy (E_d) and static refractive index (n_0) of Sb doped quaternary thin films are studied in terms of Wemple-DiDomenico (WDD) single oscillator approach. Optical band gap (E_g) is determined from Tauc's extrapolation method and is found to decrease with an increase in Sb content. Tanaka's relation is found valid for the films under study.