Photoconductivity of the Pb0.75Sn0.25Te:In alloy in an alternating electric field

Kinetics of variations in the components of total impedance for single-crystal Pb0.75Sn0.25Te:In samples is investigated upon switching on and switching off of the illumination source at temperature 4.2 K and frequency 106 Hz. The calculation carried out in the context of representation of equivalent circuits showed that the parameters of a parallel R p C p chain, which approximates the sample behavior, correlate strictly. In the region of low resistances R p , the values of C p increase abruptly following the law C p ∝ R −2 . It is of no importance what method of decreasing the resistance is used—heating of the sample or its illumination at low temperature. The obtained results were analyzed taking into account the contribution of the impurity subsystem to conductivity and the possible manifestation of Maxwell-Wagner-type effects.