Transport properties of iron-bismuthate glassy semiconductors

Abstract

Iron-bismuthate glassy semiconductors were prepared in a range of compositions and their electrical transport properties were measured in the temperature range of 100-500 K. The electrical data were analyzed in the light of the models of polaronic hopping conduction. The analysis showed that the high-temperature conductivity was well explained by the polaronic models. But these models failed to account for the decrease of the activation energy with the decrease of temperature. At lower temperatures, a variable range analysis was made. This analysis provided reasonable values of the decay constant for the localized states and also for the density of states at the Fermi level.