Abstract
The optical absorption of the as-deposited and γ-irradiated (doses of 3, 10, 12, 15 Mrad) thermally evaporated Se
85−x
Te
15
Sb
x
(x=0, 6, 9) films was measured. The refractive index n and the extinction coefficient k of the films were calculated using an analytical method developed by Zheng et al. The Urbach relation was used in the fundamental edge region to calculate the width of the band tail states. The behavior of the composition with high concentration of antimony (x=9) was attributed to the produced Se-Sb bonds and an excess of Te-Te bonds, which break the chain structure of the Se-Te system and generate defects in the film. The related optical parameters were also calculated and discussed.