Polaron transport in semiconducting silver vanadate glasses

The electrical properties of semiconducting silver vanadate glasses formed with ${\mathrm{V}}_2{\mathrm{O}}_5$ as a unique network former have been studied in the temperature range 93–423 K. The results for the silver vanadate glasses have been compared with those for the traditional vanadate glasses. The variation of the conductivity with composition for the silver vanadate glasses is much stronger than that for the traditional vanadate glasses. These results have been analyzed in terms of polaronic hopping models. Mott’s phonon-assisted hopping and variable-range hopping models are consistent qualitatively with the high-temperature and low-temperature data, respectively. However, the multiphonon-assisted hopping model of small polarons in the nonadiabatic regime, which considers the strong interaction of electrons with optical as well as acoustical phonons, can interpret quantitatively the temperature dependence of the conductivity in the entire temperature range. The parameters obtained from the fits of this model to the experimental data are reasonable and consistent with the composition.