Qasrawı, Atef Fayez Hasan

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Profile URL
https://hdl.handle.net/20.500.14411/7716
Name Variants
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
Job Title
Doçent Doktor
Email Address
atef.qasrawi@atilim.edu.tr
Main Affiliation
Department of Electrical & Electronics Engineering
Status
Former Staff
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WoS Researcher ID

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CLEAN WATER AND SANITATION6
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AFFORDABLE AND CLEAN ENERGY7
AFFORDABLE AND CLEAN ENERGY
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Scholarly Output

226

Articles

222

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84/0

Supervised MSc Theses

0

Supervised PhD Theses

0

WoS Citation Count

1984

Scopus Citation Count

2000

Patents

0

Projects

0

WoS Citations per Publication

8.78

Scopus Citations per Publication

8.85

Open Access Source

17

Supervised Theses

0

JournalCount
Crystal Research and Technology16
Journal of Electronic Materials15
physica status solidi (a)12
Materials Science in Semiconductor Processing11
Journal of Alloys and Compounds11
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2001 - 200963
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Scholarly Output Search Results

Now showing 1 - 10 of 63
  • Thumbnail Image
    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.
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    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: 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: 26
    Citation - Scopus: 26
    Photoelectronic, optical and electrical properties of TlInS2 single crystals
    (Wiley-v C H verlag Gmbh, 2003) Qasrawi, AF; Gasanly, NM
    To specify the donor energy levels in TlInS2 single crystals, the dark electrical resistivity, photoconductivity and Hall measurements were carried out in the temperature range of 100-400 K, 110-350 K and 170-400 K, respectively. The Hall measurements revealed that the crystals exhibit an anomalous behavior of Hall voltage by changing sign (from p-type to n-type conductivity) at 315 K. By means of the temperature dependence of dark electrical resistivity, Hall coefficient and photocurrent measurements the donor energy levels located at 360, 280, 152 and 112 meV were detected. The photocurrent-illumination intensity dependence follows the law I-Ph proportional to F-gamma with gamma being 1.0 (linear), 0.5 (sublinear), 1.0 (linear) and 1.3 (supralinear) at low, moderate, high and very high illumination intensities indicating the monomolecular in the bulk, bimolecular and strong recombination at the surface, respectively. The photocurrent is observed to increase with increasing temperature up to a maximum temperature (T-m) 245 K. T is observed to shift to higher temperature as F increases, and disappears in the region where I-Ph-F dependence is supralinear. The phenomenon is attributed to the exchange in the behavior of the sensitizing and recombination centers. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim.
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    Article
    Citation - WoS: 28
    Citation - Scopus: 28
    Photoelectronic and Electrical Properties of Cuin5s8< Single Crystals
    (Wiley-v C H verlag Gmbh, 2003) Qasrawi, AF; Gasanly, NM
    To identify the impurity levels in CuIn5S8 single crystals, the dark electrical conductivity and photoconductivity measurements were carried out in the temperature range of 50-460 K. The data reflect the intrinsic and extrinsic nature of the crystals above and below 300 K, respectively. Energy band gaps of 1.35 and 1.31 eV at 0 K and 300 K, were defined from the dark conductivity measurements and the photocurrent spectra, respectively. The dark and photoconductivity data in the extrinsic temperature region reflect the existence of two independent donor energy levels located at 130 and 16 meV. The photocurrent-illumination intensity dependence (F) follows the law I(ph)alphaF(gamma), with gamma being 1.0, 0.5 and 1.0 at low, moderate and high intensities indicating the domination of monomolecular, bimolecular and strong recombination at the surface, respectively. In the intrinsic region and in the temperature region where the shallow donor energy level 16 meV is dominant, the free electron life time, tau(n), is found to be constant with increasing F. In the temperature region 140 K < T < 210 K, the free electron life time increases with increasing illumination intensity showing the supralinear character. Below 140 K, tau(n) decrease with decreasing illumination intensity. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    Conference Object
    Citation - WoS: 10
    Production of Anorthite From Kaolinite and Caco3 Via Colemanite
    (Trans Tech Publications Ltd, 2004) Mergen, A; Kayed, TS; Bilen, M; Qasrawi, AF; Gürü, M
    Boron oxide has been found to be useful flux for the preparation of dense anorthite ceramics (CaO.Al2O3.2SiO(2)). Inexpensive starting materials of kaolinite, calcium carbonate and silica were used for anorthite ceramic production. Colemanite (2CaO.3B(2)O(3).5H(2)O) was added into the mixtures and the effects of colemanite upon the transformation towards anorthite and on the densification were investigated between 900-1400 degreesC. Single phase anorthite ceramic formed at lower temperatures in boron containing mixtures. Boron containing powder compacts were sintered above 90% theoretical density at 1350 degreesC.
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    Article
    Hopping Conduction in Ga4se3< Layered Single Crystals
    (Pergamon-elsevier Science Ltd, 2008) Qasrawi, A. F.; Gasanly, N. M.
    The conduction mechanism in Ga4Se3S single crystals has been investigated by means of dark and illuminated conductivity measurements for the first time. The temperature-dependent electrical conductivity analysis in the region of 100-350 K, revealed the dominance of the thermionic emission and the thermally assisted variable range hopping (VRH) of charged carriers above and below 170 K, respectively. The density of states near the Fermi level and the average hopping distance for this crystal in the dark were found to be 7.20 x 10(15) cm(-3) eV(-1) and 7.56 x 10(-6) cm, respectively. When the sample was illuminated, the Mott's VRH parameters are altered, particularly, the average hopping distance and the density of states near the Fermi level increase when light intensity increases. This action is attributed to the electron generation by photon absorption, which in turn leads to the Fermi level shift and/or trap density reduction by electron-hole recombination. (C) 2008 Elsevier Ltd. All rights reserved.
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    Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Hole-Polar Phonon Interaction Scattering Mobility in Chain Structured Tlse0.75s0.25< Crystals
    (Wiley-blackwell, 2009) Qasrawi, A. F.; Gasanly, N. M.
    In this study, the electrical resistivity, charge carriers density and Hall mobility of chain structured TlSe0.75S0.25 crystal have been measured and analyzed to establish the dominant scattering mechanism in crystal. The data analyses have shown that this crystal exhibits an extrinsic p-type conduction. The temperature-dependent dark electrical resistivity analysis reflected the existence of three energy levels located at 280 meV, 68 meV and 48 meV. The temperature dependence of carrier density was analyzed by using the single donor-single acceptor model. The carrier concentration data were best reproduced assuming the existence of an acceptor impurity level being located at 68 meV consistent with that observed from resistivity measurement, The model allowed the determination of the hole effective mass and the acceptor-donor concentration difference as 0.44m(0) and 2.2 x 10(12) cm(-3), respectively. The Hall mobility of the TlSe0.75S0.25 crystal is found to be limited by the scattering of charged carriers over the (chain) boundaries and the scattering of hole-polar phonon interactions above and below 300 K, respectively. The value of the energy barrier height at the chain boundaries was found to be 261 meV. The polar phonon scattering mobility revealed the high-frequency and static dielectric constants of 13.6 and 15.0, respectively. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Article
    Citation - Scopus: 13
    Carrier Transport Properties of Ins Single Crystals
    (2002) Qasrawi,A.F.; Gasanly,N.M.
    The electrical resistivity and Hall effect of indium sulfide single crystals are measured in the temperature range from 25 to 350 K. The donor energy levels located at 500, 40 and 10 meV below the conduction band are identified from both measurements. The data analysis of the temperature-dependent Hall effect measurements revealed a carrier effective mass of 0.95 m0, a carrier compensation ratio of 0.9 and an acoustic deformation potential of 6 eV. The Hall mobility data are analyzed assuming the carrier scattering by acoustic and polar optical phonons, and ionized impurities.