The radiation effect on optical and morphological properties of Ag-As-Te thin films

The effect of gamma irradiation on the features of AgxAs50-xTe50 with 3 <= x <= 20 films has been studied. The studies indicated that the films partially transform from the amorphous phase to a crystalline phase at low doses of gamma irradiation (0.5-3 kGy). The radiation effect on the optical spectrum of Ag-As-Te films has been studied on the deposited films before and after each radiation dose. It is found that the calculated optical band gap (E-g) decreases with increasing Ag content and at the same time decreases with the radiation dose up to 3 kGy. Increasing the radiation dose up to 3 kGy induces an indirect transition and consequently decreases the energy gap. This behavior is associated with the generation of excess electronic localized states. The surface morphology has been investigated with a scanning electron microscope (SEM). (c) 2007 Elsevier Ltd. All rights reserved.