Quantum tunnelling and the temperature dependent dc conduction in low-conductivity semiconductors

Abstract

Conventional models of electronic conduction through localised states lead to a simply activated temperature dependence, log σ α T-1, for the DC conductivity σ. But this behaviour is not always followed over the whole experimental range, and in some instances log σ α T appears to be a better description. We show some examples of this behaviour, and point out that it is a characteristic that was anticipated more than 20 years ago by a model of quantum tunnelling through a vibrating potential barrier. We show how this model can be incorporated into the small-polaron picture of electron transport to explain qualitatively a wider range of experimental behaviours. © 1985, IOP Publishing Ltd.