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Article Citation - WoS: 5Citation - Scopus: 5Acoustic Phonons Scattering Mobility and Carrier Effective Mass in In6s7< Crystals(Elsevier Science Sa, 2006) Qasrawi, A. F.; Gasanly, N. M.Systematic dark electrical resistivity and Hall coefficient measurements have been carried out in the temperature range of 170-320 K on n-type In6S7 crystals. The analysis of the electrical resistivity and carrier concentration reveals the intrinsic type of conduction with an average energy band gap of similar to 0.75 eV The carrier effective masses of the conduction and valence bands were calculated from the intrinsic temperature-dependent carrier concentration data and were found to be 0.565m(0) and 2.020m(0), respectively. The temperature-dependent Hall mobility was observed to follow the mu alpha T-3/2 law and was analyzed assuming the domination of acoustic phonons scattering. The acoustic phonons scattering mobility was calculated from the crystal's structural data with no assumptions. The experimental Hall mobility data of In6S7 crystals coincides with the theoretical acoustic phonons scattering mobility data with acoustic deformation potential of 6.4 eV. (c) 2006 Elsevier B.V. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Crystal Data and Indirect Optical Transitions in Tl2ingase4< Crystals(Pergamon-elsevier Science Ltd, 2008) Qasrawi, A. F.; Gasanly, N. M.The room temperature crystal data and the optical properties of the Bridgman method grown Tl2InGaSe4 crystals are reported and discussed. The X-ray diffraction technique has revealed that Tl2InGaSe4 is a single phase crystal of monoclinic structure. The unit cell lattice parameters, which were recalculated from the X-ray data, are found to be a = 0.77244 nm, b = 0.64945 nm, c = 0.92205 nm and beta = 95.03 degrees. The temperature dependence of the optical band gap of Tl2InGaSe4 single crystal in the temperature region of 290-500 K has also been investigated. The absorption coefficient was calculated from the transmittance and reflectance data in the incident photon energy range of 1.60-2.10 eV. The absorption edge is observed to shift toward lower energy values as temperature increases. The fundamental absorption edge corresponds to indirect allowed transition energy gap of 1.86 eV that exhibited a temperature coefficient gamma = -3.53 x 10(-4) eV/K. (C) 2007 Elsevier Ltd. All rights reserved.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.
