Determination of trapping center parameters of Tl2InGaS4-layered crystals by thermally stimulated current measurements

We have carried out thermally stimulated current measurements on as-grown Tl2InGaS4-layered single crystals in the low temperature range 10-60 K with different heating rates. We found experimental evidence for the presence of two shallow hole trapping centers with activation energies of 4 and 10 meV. We have determined the trap parameters using various methods of analysis, and these agree with each other. Their capture cross-sections have been found to be 6.5 × 10−26 and 4.0 × 10−25 cm2, respectively, and their concentrations are 2.1 × 1012 and 6.5 × 1012 cm−3, respectively. It is concluded that in these centers retrapping is negligible, as confirmed by the good agreement between the experimental results and the theoretical predictions of the model that assumes slow retrapping.