Experimental investigation on some electrical parameters of In 10− xSn xSe 90 ( x = 2, 4, 6, and 8) chalcogenide glasses before and after γ-irradiation

Abstract

Some electrical parameters of In 10− x Sn x Se 90 ( x = 2, 4, 6, and 8) chalcogenide glasses before and after γ-irradiation, at doses of 8, 16 and 32 kGy, are reported and discussed. I– V measurements, for both un-irradiated and gamma irradiated glasses, have been carried out in the temperature range of 170–290 K for different electric fields. The recorded I– V characteristics reveal that the studied glasses exhibit ohmic and non-ohmic behavior at low and high fields, respectively. Analysis of the experimental data, for un-irradiated and gamma irradiated samples, in the high field range confirms the presence of space charge limited conduction (SCLC) in the glasses under investigation, while conduction mechanism in low temperature region occurs via variable range hopping (VRH) of charge carriers in the band tail of the localized states. The DC conductivity is found to increase with Sn concentration up to 6 at.% of Sn, after which it decreases. The post gamma irradiation conductivity is, in general, improved at moderated doses i.e., 8 and 16 kGy. The density of localized states N( E F), before and after irradiation, is increased with incorporation of Sn up to 6 at.%, after which a drastic decrease is observed to occur. This is attributed to an increase in the average single bond energy of In 2Sn 8Se 90 which decreases the conductivity and the density of localized states for this particular composition. The hopping energy W and hopping distance R hop have also been calculated and their values agree fairly well with the concept of (VRH) model and are in support of our results regarding the behavior of the electrical conductivity.