Abstract
Single crystals of TlInS2:Cu were grown by the modified Bridgman method. The dielectric behavior of TlInS2:Cu was investigated using the impedance spectroscopy technique. The real (epsilon(1)), imaginary (epsilon(2)) parts of complex dielectric permittivity and ac conductivity were measured in the frequency range (42-2 x 10(5)) Hz with a variation of temperature in the range from 291 K to 483 K. The impedance data were presented in Nyquist diagrams for different temperatures. The frequency dependence of sigma(tot) (omega) follows the Jonscher's universal dynamic law with the relation sigma(tot) (omega)=sigma(dc)+A omega(s), (where s is the frequency exponent). The mechanism of the ac charge transport across the layers of TlInS2:Cu single crystals was referred to the hopping over localized states near the Fermi level. The examined system exhibits temperature dependence of sigma(ac) (omega), which showed a linear increase with the increase in temperature at different frequencies. Some parameters were calculated as: the density of localized states near the Fermi level, N-F, the average time of charge carrier hopping between localized states, tau, and the average hopping distance, R. (C) 2013 Elsevier B.V. All rights reserved