Investigation of Photoelectrical and Current Transient Behaviour of TlBr.

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 conductivity of about 0.78 eV could stand for several mechanisms, e.g., electronic and ionic conductivity. From the spectral dependencies of photocurrent several defect-related maxima in the region between 1 and 2.5 eV were identified, being dependent on sample prehistory, i.e., its excitation by light and/or voltage. The transient photocurrent kinetics had demonstrated a complex behaviour that could be explained by the combined influence of electron generation/recombination processes superimposed upon the effect of ionic conductivity. The results indicate that ionic conductivity can take place also at - 20 C, though its influence is less because of the thermally activated character. [ABSTRACT FROM AUTHOR]