Specific Features of Photoconductivity of Tl1-xIn1-xSnxSe2 Monocrystals at Low Temperatures

The photoconductivity spectra in the temperature range T≈36-200 K and the spectra of thermostimulated currents in the temperature range T≈70-300 K of Tl1-xIn1-xSnxSe2 single crystals obtained by directional crystallization of Bridgman-Stockbarger have been studied. The induced photoconductivity and long-term photoconductivity relaxation processes have been found. To interpret the found results, a model of two-center recombination has been suggested. It is illustrated that the role of the r-centers of slow recombination are formed by Tl vacancies. On the basis of the studies of the spectra of thermally stimulated currents, the thermal energy of electrons activation with t-levels of adhesion has been determined.