Effect of laser irradiation on thermal and optical properties of selenium–tellurium alloy

The crystallization parameters such as glass transition temperature (Tg), onset crystallization temperature (Tc), peak crystallization temperature (Tp) and enthalpy released (ΔHC) of the bulk Se–Te chalcogenide glass has been studied by using Differential Scanning Calorimeter (DSC), under non-isothermal condition at a heating rate of 20 K/min. The values of Tg, Tc, Tp and ΔHC with and without laser irradiation for different exposure time have been studied. The optical absorption of pristine and laser irradiated thermally evaporated Se–Te films has been measured. The films shows indirect allowed interband transition that is influenced by the laser irradiation. The optical energy gap has been found to decrease from 1.61 to 1.38 eV with increasing irradiation time from 5 to 20 min. The results have been analyzed on the basis of laser irradiation-induced defects in the film.