Compositional dependence optical properties study of As40Se60 − xSbx thin films

Thin films were thermally evaporated from the bulk glasses of As₄₀Se_60 − xSb_x (with x = 0, 5, 10, 15 at.%) under high vacuum. We have characterized the deposited films by Fourier Transform Infrared spectroscopy. The relationship between the structural and optical properties and the compositional variation has been investigated. Increasing Sb content was found to affect the thermal and optical properties of these films. Non-direct electronic transition was found to be responsible for the photon absorption inside the investigated films. It was found that, the optical band gap E_o decreases while the width of localized states (Urbach energy) E_e increases.