Abstract
The photoβexcitation effect on the current transport mechanism in TlInS~2~ crystals has been studied by means of dark and illuminated conductivity measurements. The temperatureβdependent electrical conductivity analysis in the temperature region of 110β340 K revealed the domination of the thermionic emission and the thermally assisted variable range hopping (VRH) of charge carriers above and below 160 K, respectively. Above 160 K, the conductivity activation energies in the dark are found to be 0.28 and 0.15 eV in the temperature regions of 340β240 K and 230β160 K, respectively. In the temperature region of 110β150 K, the dark variable range hopping analysis revealed a density of localized states of 1.99Γ10^22^ cm^β3^eV^β1^, an average hopping distance of 0.53 nm and an average hopping energy of 79.65 meV. When the sample was photoβexcited, the values of the conductivity activation energies, the density of localized states near the Fermi level and the average hopping energy were observed to decrease sharply with increasing illumination intensity. On the other hand, the average hopping distance increased with rising illumination intensity. Such behaviours were attributed to the Fermi level shift and/or trap density reduction by electronβhole recombination. (Β© 2010 WILEYβVCH Verlag GmbH & Co. KGaA, Weinheim)