Iron doping of semiconducting bismuth alkali borate glasses

Several properties of semiconducting Fe2O3-Bi2O3-Li2B4O7 glasses have been investigated. These properties include Mossbauer, differential scanning calorimeter (DSC), density, thermoelectric power and DC conductivity. Mossbauer spectroscopy results revealed that the relative fraction of Fe2+ increases with an increasing Fe2O3 content. Density was observed to decrease with an increase in Fe2O3 content. The glasses are n-type semiconducting. The experimental data have been analyzed in the light of theoretical models. It has been observed that the general behavior of electrical conductivity is similar for all glass compositions. The high-temperature conductivity data are consistent with Mott's models of phonon-assisted polaronic hopping in the non-adiabatic regime. The physical parameters obtained from the best fits of these models are found reasonable and consistent with glass compositions. The conductivity was primarily determined by carrier mobility. (c) 2006 Elsevier B.V. All rights reserved.