The dielectric and impedance spectra of TlGaSe2 crystals have been studied at temperatures in the 100–500 K range in the alternating current (AC [Formula: see text]1 V). It has been shown that the conductivity of TlGaSe2 crystals is mainly an ionic characteristic at temperatures above 400 K. The well-defined peak at the frequency dependence of the imaginary part of impedance [Formula: see text] is observed in the 215–500 K temperature range. In a constant field, there occurs a significant decrease in electrical conductivity [Formula: see text] in due course. The ionic contribution to conductivity (76% at [Formula: see text]) has been estimated from a kinetic change in electrical conductivity [Formula: see text] under the influence of a constant electric field. The diagram analysis in a complex plane [Formula: see text] has been conducted by applying the method of an equivalent circuit of the substation. It has been determined that the average relaxation time of the electric module of the sample is [Formula: see text].

In this work, the dielectric and electrical properties of TlInS2 crystal have been studied in the temperature range of 300–550 K before and after being implanted with H[Formula: see text] ion. The dielectric parameters such as the real and imaginary parts of permittivity, impedance and dielectric loss have been investigated in this temperature range. The role of free ions in the relaxation process when f [Formula: see text] 10 kHz on the basis of the study of dielectric parameters in the frequency range of 25–106 Hz has been determined. It has been observed that the interdependencies of the real and imaginary parts of dielectric permittivity go beyond the standard.