Mott type variable range hopping conduction and magnetoresistance in p-type CuIn3Te5 semiconductor compound.

Variable range hopping (VRH) conduction of Mott type for a constant and non-vanishing density of states at the Fermi level is observed over a wide range of temperature between 45 and 210K in the ordered defect compound CuIn₃Te₅ (CIT135). For this type of electrical conduction at a very high temperature, not reported before in elemental, II-VI, and I-III-VI₂ compound semiconductors, we employed three different methods to analyze the data and to confirm this behavior. The occurrence of VRH at very high temperatures is explained as due to the presence of the electrically inactive (In_Cu⁺² + V_Cu^-1)) donor-acceptor defect pairs in CIT135. This defect-pair partially annihilates the shallow acceptor defect state Cu vacancy, which is responsible for the activated electrical conductivity observed in p-type ternary I-III-VI₂ chalcopyrite compounds in the temperature range of liquid nitrogen. In such conditions, the only acceptor level available for electrical conduction in CIT135 is a deep acceptor state whose activation energy is about 200meV and cannot be activated below about 200K. Hence, the VRH conduction mechanism dominates the electrical properties of this material up to about 200K. The study of the temperature and magnetic field dependence of the magnetoresistance (MR) up to 27 T is made by taking into consideration different theoretical models. To explain the negative MR at lower fields, the theory based on quantum interference is used. At higher magnetic fields, the MR becomes positive and is explained with the model based on the shrinkage of the wave function. [ABSTRACT FROM AUTHOR]