Photoelectrical Phenomena and Current Kinetics in TlBr

Abstract

Photoelectrical and current transient properties of TlBr were investigated in the temperature region from –20 °C up to +20 °C, in which the effect of ionic conductivity changes significantly. The thermal activation energy value of conduc-tivity of about 0.78 eV could stand for several mechanisms, e.g., electronic and ionic conductivity. From the spectral de-pendencies of photocurrent several defect-related maxima in the region between 1 eV and 2.5 eV were identified, being dependent on sample prehistory, i. e., its excitation by light and/or voltage. The transient photocurrent kinetics have demonstrated a complex behaviour that could be explained by the combined influence of electron genera-tion/recombination processes superimposed upon the effect of ionic conductivity. The results indicate that ionic conduc-tivity can take place also at –20 °C, though its influence is less because of the thermally activated character.