DC electrical properties of cadmium vanadate glassy semiconductors: a comparison with traditional glasses

The temperature and composition dependence of the electrical conductivity of cadmium vanadate semiconducting glasses formed with V2O5 as a unique network former has been studied in this paper. The results for these glasses have been compared with those for traditional vanadate glasses formed with different traditional network formers (phosphate, borate, etc). The variation of the conductivity and the activation energy with composition for the cadmium vanadate glasses is much stronger than that for the traditional vanadate glasses. The strong compositional variation of the conductivity and the activation energy for the present glasses has been attributed to the significant structural changes observed in the Fourier transform infrared (FT-IR) spectra due to the introduction of a CdO modifier in the glassy matrix. The experimental results have been analysed in the light of the existing theories of polaronic conduction. It has been observed that the electrical conduction at high temperatures in these glass compositions is described by Mott's phonon-assisted hopping model, while the low-temperature data in a limited temperature range are consistent with the variable-range hopping model. The parameters obtained from the fits of these models to the experimental data are reasonable