Transport and recombination kinetics in TlGaTe2 crystals



In this work, the transport and recombination mechanisms as well as the average hole-relaxation time in TlGaTe2 have been investigated by means of temperature-dependent dark electrical conductivity, photoexcitation intensity-dependent photoconductivity, and Hall effect measurements, respectively. The experimental data analysis revealed the existence of a critical temperature of 150 K. At this temperature, the transport mechanism is disturbed. The dark conductivity data analysis allowed the determination of an energy state of 258 meV. The hole-relaxation time that was determined from the Hall mobility data was observed to increase with decreasing temperature. The behavior was attributed to the hole–thermal lattice scattering interactions. At fixed photoexcitation intensity, the photocurrent Iph decreases with decreasing temperature down to 150 K. Below this temperature it changes direction. The latter data allowed the determination of the recombination center energy as 110 meV. On the other hand, at fixed temperature and variable illumination intensity, the photocurrent follows the relation IphαFn (the value of the exponent, n, decreases with decreasing temperature).