Variable range hopping conductivity at low temperatures in CuGaS2 single crystals

Abstract

AbstractCharge transport mechanism in the CuGaS2 single crystals in a wide temperature range 4.3‐300 K are investigated. In the high temperature range 100‐300 K, the electrical conductivity is predominantly provided by thermally excited impurity charge carriers in the allowed energy band. The activation energy for impurity charge carriers in this temperature range is equal to 12 meV. In the low temperature range (T < 100 K), the electrical conductivity occurs through charge carrier hopping between localized states lying in a narrow energy band near the Fermi level (so called Mott conductivity). The density of localized states near the Fermi level, the width of the optimum energy band of localized levels, concentration of localized states and the average carrier‐hopping distances are estimated for different temperatures. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)