Low temperature electrical impedance spectroscopy characterization of n type CuInSe2 semiconductor compound

In this report, the ternary chalcopyrite semiconductor n-CulnSe2 (n-CIS112) was studied using impedance spectroscopy (IS) over a wide range of temperatures [80 K, 300 K] and frequencies [20 Hz, 1 MHz]. The ingot was grown by vertical Bridgman technique. The experimental data are analyzed to estimate the activation and relaxation energies. The activation energies agree with those reported from Hall effect measurements. The predominance of both “bulk” and “grain-boundary” contributions to the electrical conduction is confirmed by using impedance and modulus formalism. AC electrical conductivity data σac(ω,T) for n-CulnSe2 are discussed using the theoretical Overlapping Large Polaron Tunneling process. •AC electrical properties are studied for the first time in n-CuInSe2 from 80 K to 300 K.•The frequency dependence of the complex impedance is analyzed.•The activation energy for the relaxation and conduction process are estimated.•The AC electrical conductivity is explained by the OLPT theoretical mechanism.