PREPARATION AND INVESTIGATION ON GLASSES IN THE TE46AS32GE10SI12 AND TE41AS37GE10SI12 SYSTEMS

Thin films of Te46-xAs32+xGe10Si12 (x = 0, 5) of different thicknesses are deposited on glass substrate by vacuum evaporation. X-ray diffrac tion revealed the formation of amorphous films. The value of the optic al band gap, E(g), is found to increase with the thickness of the film s and with increasing As content. The films are heat treated at differ ent elevated temperatures from 298 to 423 K. The values of E(g) are fo und to decrease with increasing temperature of heat treatment. The ban d tail, E(e), obey Urbach's empirical relation.