Qasrawı, Atef Fayez Hasan

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https://hdl.handle.net/20.500.14411/7716
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Qasrawi, Atef Fayez
Atef Fayez Hasan, Qasrawı
Qasrawı,A.F.H.
Qasrawi,A.F.H.
Q., Atef Fayez Hasan
Q.,Atef Fayez Hasan
Atef Fayez Hasan, Qasrawi
Qasrawi, Atef Fayez Hasan
A.F.H.Qasrawı
A.F.H.Qasrawi
A., Qasrawi
A.,Qasrawı
Qasrawı, Atef Fayez Hasan
Qasrawi, A. F.
Qasrawi,A.F.
Qasrawi, AF
Qasrawi, Atef F.
Qasrawi, Atef A.
Qasrawi, Atef Fayez
Qasrawi, Atef F.
Qasrawi, Atef A.
Qasrawi, Atef
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Doçent Doktor
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atef.qasrawi@atilim.edu.tr
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Department of Electrical & Electronics Engineering
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Former Staff
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Scholarly Output

222

Articles

218

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Journal of Electronic Materials15
Crystal Research and Technology13
physica status solidi (a)12
Journal of Alloys and Compounds11
Materials Science in Semiconductor Processing11
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Author: Gasanly, N. M.Has files: false

Scholarly Output Search Results

Now showing 1 - 10 of 49
  • Thumbnail Image
    Conference Object
    Citation - WoS: 15
    Citation - Scopus: 15
    Refractive Index, Static Dielectric Constant, Energy Band Gap and Oscillator Parameters of Ga2ses Single Crystals
    (Wiley-v C H verlag Gmbh, 2007) Qasrawi, A. F.; Gasanly, N. M.
    The optical properties of Bridgman method grown Ga2SeS crystals have been investigated by means of room-temperature transmittance and reflectance spectral analysis. The optical data have revealed direct and indirect allowed transition band gaps of 2.49 and 2.10 eV, respectively. The room-temperature refractive index, which was calculated from the reflectance and transmittance data, allowed the identification of the dispersion and oscillator energies, static dielectric constant and static refractive index as 20.93 eV and 4.01 eV, 6.21 and 2.49, respectively.
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    Conference Object
    Citation - WoS: 2
    Citation - Scopus: 2
    Temperature-Dependent Capacitance-Voltage Biasing of the Highly Tunable Tlgate2 Crystals
    (Elsevier Science Bv, 2012) Qasrawi, A. F.; Gasanly, N. M.
    The temperature effects on the capacitance-voltage characteristics as well as the room temperature capacitance-frequency characteristics of TlGaTe2 crystals are investigated. A very wide range of linearly varying tunable capacitance from 6.0 mu F to 60 pF was recorded. The capacitance-voltage characteristics, being recorded in the temperature range of 290-380 K, revealed a linear increase in the build in voltage associated with exponential decrease in the density of non-compensated ionized carriers with increasing temperature. The high temperature (up to 380 K) biasing ability, the linear tunability and the high dielectric constant values ( similar to 10(3)) make the TlGaTe2 crystals applicable in microelectronic components. (C) 2012 Elsevier B.V. All rights reserved.
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    Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Transport and Recombination Kinetics in Tlgate2 Crystals
    (Wiley-blackwell, 2009) Qasrawi, A. F.; Gasanly, N. M.
    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 I-ph 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 1 10 meV On the other hand, at fixed temperature and variable illumination intensity, the photocurrent follows the relation I-ph alpha F-n (the value of the exponent, it, decreases with decreasing temperature). (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Observation of in Situ Enhanced Crystallization, Negative Resistance Effect and Photosensitivity in Tl2ingase4< Crystals
    (Elsevier Sci Ltd, 2021) Qasrawi, A. F.; Irshaid, Tahani M. A.; Gasanly, N. M.
    In this work, we report the properties of Tl2InGaSe4 crystals as multifunctional material. Namely, Tl2InGaSe4 crystals are grown by the modified Bridgman method using mixtures of TlInSe2 (50%) and TlGaSe2 (50%) single crystals. The enhanced crystallization and structural stabilities are monitored by the X-ray diffraction technique during the in situ heating and cooling cycles. The structural analyses on the Tl2InGaSe4 crystals revealed domination of both of the monoclinic and tetragonal phases in the crystals. In addition, the produced crystals are used to fabricate Schottky diodes. While the scanning electron microscopy has shown that the crystals are composed of layered nanosheets, the electrical analyses have shown that the crystals exhibit light photosensitivity of 12.7 under tungsten light illumination of 10 kLuxes. The attenuation in the electrical parameters of the Ag/Tl2InGaSe4/C diodes presented by series resistance, barrier height and ideality factor upon light excitations make them promising for applications in optoelectronics as switches and photodetectors. Moreover, the alternating electrical signals analyses on the capacitance spectra displayed resonance -antiresonance oscillations in the frequency domain of 83-100 MHz. The resistance spectra also exhibited negative resistance effect in the range of 55-135 MHz. These features of the device make it suitable for use as microwave resonators and memory devices as well.
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    Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Acoustic 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.
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    Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Structural, Electrical and Anisotropic Properties of Tl4se3< Chain Crystals
    (Pergamon-elsevier Science Ltd, 2009) Qasrawi, A. F.; Gasanly, N. M.
    The structure, the anisotropy effect on the current transport mechanism and the space charge limited current in Tl4Se3S chain crystals have been studied by means of X-ray diffraction, electrical conductivity measurements along and perpendicular to the crystal's c-axis and the current voltage characteristics. The temperature-dependent electrical conductivity analysis in the region of 150-400 K, revealed the domination of the thermionic emission of charge carriers over the chain boundaries above 210 and 270 K along and perpendicular to the c-axis, respectively. Below these temperatures, the variable range hopping is dominant. At a consistent temperature range, the thermionic emission analysis results in conductivity activation energies of 280 and 182 meV, along and perpendicular to the c-axis, respectively. Likewise, the hopping parameters are altered significantly by the conductivity anisotropy. The current-voltage characteristics revealed the existence of hole trapping state being located at 350 meV above the valence band of the crystal. (C) 2009 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Article
    Citation - WoS: 8
    Citation - Scopus: 8
    Temperature- and Photo-Excitation Effects on the Electrical Properties of Tl4se3< Crystals
    (Iop Publishing Ltd, 2009) Qasrawi, A. F.; Gasanly, N. M.
    The extrinsic energy states and the recombination mechanism in the Tl4Se3S chain crystals are being investigated by means of electrical and photoelectrical measurements for the first time. The electrical resistivity is observed to decrease exponentially with increasing temperature. The analysis of this dependence revealed three impurity levels located at 280, 68 and 48 meV. The photocurrent is observed to increase as temperature decreases down to a minimum temperature T-m=200 K. Below this temperature the photocurrent decreases upon temperature lowering. Two photoconductivity activation energies of 10 and 100 meV were determined for the temperature ranges below and above T-m, respectively. The photocurrent (I-ph) versus illumination intensity (F) dependence follows the I-ph proportional to F-gamma law. The value of gamma decreases from similar to 1.0 at 300K to similar to 0.34 at 160K. The change in the value of gamma with temperature is attributed to the exchange of roles between the monomolecular recombination at the surface near room temperature and trapping centers in the crystal, which become dominant as temperature decreases.
  • Thumbnail Image
    Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Space-charge-limited currents and photoconductive properties of Tl2InGaSe4 layered crystals
    (Taylor & Francis Ltd, 2008) Qasrawi, A. F.; Gasanly, N. M.
    The extrinsic electronic parameters of Tl2InGaSe4 layered crystals were investigated through measurement of the temperature-dependent dark conductivity, space-charge-limited currents and photoconductivity. Analysis of the dark conductivity reveals the existence of two extrinsic energy levels at 0.40 and 0.51 eV below the conduction band edge, which are dominant above and below 260 K, respectively. Current-voltage characteristics show that the one at 0.51 eV is a trapping energy level with a concentration of (4.8-7.7) x 10(10) cm(3). Photoconductivity measurements reveal the existence of another energy level located at 0.16 eV. In the studied temperature range, the photocurrent increases with increasing temperature. The dependence of the photoconductivity on the incident light intensity exhibits a linear recombination character near room temperature and a supralinear character as the temperature decreases. The change in recombination mechanism is attributed to an exchange in the behavior of sensitizing and recombination centres.
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    Article
    Citation - WoS: 5
    Citation - Scopus: 6
    Photoelectronic and Electrical Properties of Tl2ingas4< Layered Crystals
    (Pergamon-elsevier Science Ltd, 2007) Qasrawi, A. F.; Gasanly, N. M.
    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 below 300 K, respectively. The photoconductivity measurements reflected the existence of two other energy levels located at 0.28 eV and 0.19 eV at high and low temperatures, respectively. The photocurrent is observed to increase with increasing temperature up to a maximum temperature of 330 K. The illumination dependence of photoconductivity is found to exhibit supralinear recombination in all the studied temperature ranges. The change in recombination mechanism is attributed to exchange in the behavior of sensitizing and recombination centers. (C) 2006 Elsevier Ltd. All rights reserved.
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    Article
    Citation - WoS: 7
    Citation - Scopus: 6
    Temperature-Dependent Structural Transition, Electronic Properties and Impedance Spectroscopy Analysis of Tl2ingas4< Crystals Grown by the Bridgman Method
    (Elsevier Sci Ltd, 2018) Qasrawi, A. F.; Alkarem, Qotaibah A.; Gasanly, N. M.
    In this work, we report the temporary structural modifications associated with the in situ heating of the Tl2InGaS4 crystals in the temperature range of 300-420 K. The analysis of the X-ray diffraction patterns revealed the temperature-independent possible phase transformations between the monoclinic and triclinic phases. The temperature analysis of the lattice parameters, crystallite size, strain, dislocation density and stacking faults has shown a temporary enhancement in the crystallinity of this compound above 375 K. Significant increase in the grain size accompanied to decrease in the strain, defect density and stacking faults was observed above this temperature. The scanning electron microscopy imaging has shown that the crystals are layer structured with high quality layers of thicknesses of similar to 12 nm. In addition the energy dispersive X-ray analysis has shown that the crystal comprise no detectable impurity. Moreover, the room temperature optical characterizations has shown that the Tl2InGaS4 exhibit an energy band gap of 2.5 eV. The temperature dependent electrical resistivity measurements indicated highly resistive crystal with activation energy values of 0.84 and 0.19 eV above and below 375 K, respectively. On the other hand, room temperature impedance spectroscopy analysis in the frequency domain of 10-1800 MHz has shown that the crystal exhibits negative resistance and negative capacitance effects below and above 1580 MHz. The crystals are observed also to behave as band stop filter with notch frequency of 1711 MHz.