Photoelectrical properties of TlGaSe2 single crystals

The spectral distribution of photocurrent (PC) of TlGaSe2 single crystals in the range of wavelengths between 500 nm and 700 nm possesses a single maximum at 2.04 eV corresponds to the direct energy band gap of this crystal. The PC is enhanced dramatically by pre-illuminations at low temperatures with band gap light. The temperature dependence of PC of the sample investigated in the temperature range from 80 K to 300 K at constant heating rate shows that the overlapping peaks in the PC spectrum are direct reflection of the Thermally Stimulated Current (TSC) associated with the several trapping levels. The PC response is strongly dependent on the degree of occupancy of traps. The wavelength at the maximum of the PC spectrum is found to be dependent on the wavelength scan direction being up or down. The ferroelectric phase transitions of TlGaSe2 are detected at similar to 108 K and similar to 118 K in the PC spectrum. (C) 2014 Elsevier Masson SAS. All rights reserved.


Photoelectronic and electrical properties of Tl2InGaS4 layered crystals
Qasrawi, A. F.; Hasanlı, Nızamı (2007-01-01)
Tl2InGaS4 layered crystals are studied through the dark electrical conductivity, space charge limited current and illumination- and temperature-dependent photoconductivity measurements in the temperature regions of 220-350 K, 300-400 K and 200-350 K, respectively. The space charge limited current measurements revealed the existence of a single discrete trapping level located at 0.44 eV. The dark electrical conductivity showed the existence of two energy levels of 0.32 eV and 0.60 eV being dominant above and...
Excitation and temperature tuned photoluminescence in Tl2In2S3Se layered crystals
Güler, Işıkhan; Hasanlı, Nızamı (2006-12-01)
Photoluminescence spectra of Tl2In2S3Se layered single crystals have been studied in the wavelength region of 535-725 nm and in the temperature range of 22-58 K. Two photoluminescence bands centered at 564 (2.20 eV, A-band) and 642 nm (1.93 eV, B-band) were observed at T = 22 K. Variations of both bands have been investigated as a function of excitation laser intensity in the range from 16 to 516 mW cm(-2). These bands are attributed to recombination of charge carriers through donor-acceptor pairs located i...
Donor-acceptor pair recombination in AgIn5S8 single crystals
Hasanlı, Nızamı; Aydinli, A; Gurlu, O; Yilmaz, I (1999-03-15)
Photoluminescence (PL) spectra of AgIn5S8 single crystals were investigated in the 1.44-1.91 eV energy region and in the 10-170 K temperature range. The PL band was observed to be centered at 1.65 eV at 10 K and an excitation intensity of 0.97 W cm(-2). The redshift of this band with increasing temperature and with decreasing excitation intensity was observed. To explain the observed PL behavior, we propose that the emission is due to radiative recombination of a donor-acceptor pair, with an electron occupy...
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Güler, Işıkhan; Hasanlı, Nızamı (2007-12-01)
The optical properties of TlGaSeS layered single crystals have been investigated by measuring the transmissions and the reflections in the wavelength region between 400 and 1100 nm. The optical indirect transitions with a band gap energy of 2.27 eV and direct transitions with a band gap energy of 2.58 eV were found by means of the analysis of the absorption data at the room temperature. The rate of change of the indirect band gap with temperature, that is, gamma = -3.2 x 10(-4) eV/K, was determined from the...
Visible photoluminescence from chain Tl4In3GaSe8 semiconductor
Hasanlı, Nızamı (IOP Publishing, 2006-07-05)
The emission band spectra of undoped Tl4In3GaSe8 chain crystals have been studied in the 16-300 K temperature range and the 535-740 nm wavelength range. Two visible photoluminescence bands centred at 589 and 633 nm were observed at T = 16 K. Variations of both bands have been investigated over a wide range of laser excitation intensity ( 3 x 10(-4) -1.2 W cm(-2)). Radiative transitions with energies of 2.10 and 1.96 eV from two upper conduction bands to two shallow acceptor levels (0.03 and 0.01 eV), respec...
Citation Formats
S. Özdemir, “Photoelectrical properties of TlGaSe2 single crystals,” SOLID STATE SCIENCES, pp. 25–31, 2014, Accessed: 00, 2020. [Online]. Available: