Frequency dependent conductivity of cadmium vanadate glassy semiconductor

Abstract

We have studied the frequency dependent conductivity of the semiconducting cadmium vanadate glasses of compositions xV2O5–(1−x)CdO where x = 0.6, 0.7, 0.8 and 0.9 in the temperature range 93–423 K and in the frequency range 10 Hz–2 MHz. We have observed sub-linear frequency dependence and weak temperature dependence of the ac conductivity. We have analyzed the experimental results in the framework of various theoretical models based on quantum mechanical tunneling and classical hopping over barriers. It has been observed that the temperature and frequency dependence of the ac conductivity is consistent with the overlapping large polaron tunneling model, while the classical barrier hopping models fail to interpret the data.