Characteristics of photoconductivity in Tl₂S layered single crystals

Abstract

Abstract In this work the photoconductivity measurements are carried out for single crystals of the Tl 2 S compound by using both pulsed excitation (a.c) and steady state (d.c) methods in order to elucidate the nature of photoconductivity (PC) in this compound. Results are reported in the temperature range from 77 K to 300 K, excitation intensity range from 1800 V to 5200 V Lux, applied voltage range from 2 V to 14 V, and wavelength range from 840 nm to 1450 nm. Both of the ac‐photoconductivity (ac‐PC) and the spectral distribution of the photocurrent are studied at different values of light intensity, applied voltage, and temperature. Dependencies of the carrier lifetime on the light intensity, the applied voltage, and the temperature have also been investigated as results of the ac‐PC measurements. The temperature dependence of the energy gap width has been described as a result of studying the dc‐photoconductivity (dc‐PC). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)