Effect of gamma irradiation on some electrical properties and optical band gap of bulk Se92Sn8 chalcogenide glass

Some electrical properties and optical band gap of un-irradiated and gamma irradiated, at different doses of 4, 20 and 33 kGy, of bulk Se92Sn8 glass have been studied. The I–V measurements, carried out in the temperature range of 187–296 K, have been done at different electric fields and exhibit an ohmic and a non-ohmic behavior at low and high fields, respectively, for both un-irradiated and γ-irradiated glass. In both cases, the conduction mechanism occurs due to Variable Range Hopping (VRH) of charge carriers in the localized states near Fermi level. As the γ-doses increase the amorphicity of the glass decreases, as monitored by the disorder parameter To, and the density of states N(EF) increases up to 20 kGy after which a reverse in both parameters is observed. The increase in γ-doses increase the values of the allowed indirect optical band gap Eg of Se92Sn8 glass up to 20 kGy after which Eg decreases but remain higher than that of un-irradiated glass.