2 results
Search Results
Now showing 1 - 2 of 2
Article Citation - WoS: 1Citation - Scopus: 1Optoelectronic Properties of Tl3inse4 Single Crystals(Taylor & Francis Ltd, 2010) Qasrawi, A. F.; Gasanly, N. M.The crystal structure, temperature-dependent electrical conductivity, Hall coefficient, current-voltage characteristics, absorption spectra and temperature- and illumination-dependent photoconductivity of Tl3InSe4 single crystals were investigated. Tl3InSe4 crystallises in a body-centred lattice with tetragonal symmetry and belongs to the space group [image omitted]. The crystals are extrinsic p-type semiconductors and exhibit a conductivity conversion from p- to n-type at a critical temperature, Tc, of 283 K. They are observed to have Schottky diode properties in an Ag/Tl3InSe4/Ag Schottky barrier device structure. The absorption spectra displays two maxima, one related to an indirect energy band gap of 1.20 eV and another corresponding to exciton transitions. The photocurrent is observed to be strongly affected by the conductivity type of the crystal. The incident light intensity dependence of the photocurrent is found to be supralinear, linear and sublinear, indicating strong recombination at the surface, monomolecular recombination and bimolecular recombination, respectively, in the regions where the sample is p-type ([image omitted]), at [image omitted], and in the n-type region ([image omitted]). In the n-type region, the photocurrent increases with decreasing temperature down to 250 K, below which the photocurrent is temperature invariant. The change in recombination mechanism is attributed to the change in the behaviour of sensitising and recombination centres.Article Citation - WoS: 2Citation - Scopus: 3Crystal Data and Some Physical Properties of Tl2ingate4< Crystals(Wiley-v C H verlag Gmbh, 2007) Qasrawi, A. F.; Gasanly, N. M.The room temperature crystal data, Debye temperature, dark and photoelectrical properties of the Bridgman method grown Tl2InGaTe4 crystals are reported for the first time. The X-ray diffraction technique has revealed that Tl(2)lnGaTe(4) is a single phase crystal of tetragonal body-centered structure belonging to the D-4H(18) - I4mcm space group. A Debye temperature of 124 K is calculated from the results of the X-ray data. The current-voltage measurements have shown the existence of the switching property of the crystals at a critical voltage of 80 V. The dark electrical resistivity and Hall effect measurements indicated the n-type conduction with an electrical resistivity, electron density and Hall mobility of 2.49x 10(3) Omega cm, 4.76x 10(12) cm(-3) and 527 cm V-2(-1) s(-1), respectively. The photosensitivity measurements on the crystal revealed that, the variation of photocurrent with illumination intensity is linear, indicating the domination of monomolecular recombination at room temperature. Moreover, the spectral distribution of the photocurrent allowed the determination of the energy band gap of the crystal studied as 0.88 cV.
