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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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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Scholarly Output Search Results

Now showing 1 - 10 of 165
  • Thumbnail Image
    Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Effects of Laser Excitation and Temperature on Ag/Gase0.5< Microwave Filters
    (Springer, 2014) Qasrawi, A. F.; Khanfar, H. K.
    The effects of temperature, illumination, and microwave signals on Ag/GaS0.5S0.5/C Schottky-type microwave filters have been investigated. The devices, which were produced from thin layers of GaSe0.5S0.5 single crystal, had room temperature barrier height and ideality factor of 0.65 eV and 3.28, respectively. Barrier height increased uniformly with increasing temperature, at 2.12 x 10(-2) eV/K, and the ideality factor approached ideality. The devices can even function at 95A degrees C. A current switching phenomenon from low to high injection ("On/Off") was also observed; this current switching appears at a particular voltage, V (s), that shifts toward lower values as the temperature is increased. When the devices were reverse-biased and illuminated with a laser beam of wavelength 406 nm, a readily distinguishable V (s) was observed that shifted with increasing laser power. When the devices were run in passive mode and excited with an ac signal of power 0.0-20.0 dBm and frequency 0.05-3.0 GHz they behaved as band filters that reject signals at 1.69 GHz. Device resistance was more sensitive to signal amplitude at low frequencies (50 MHz) than at high frequencies. The features of these Ag/GaS0.5S0.5/C Schottky devices imply that they may be used as optical switches, as self standing, low band-pass, band reject filters, and as high band-pass microwave filters.
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    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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    Article
    Citation - WoS: 4
    Citation - Scopus: 4
    Physical Properties of Neodymium Tin Oxide Pyrochlore Ceramics
    (de Gruyter Poland Sp Zoo, 2017) Saleh, Adli A.; Qasrawi, A. F.; Yumusak, G.; Mergen, A.
    In this work, physical properties of neodymium tin oxide pyrochlore ceramics prepared by solid state reaction technique are investigated by means of X-ray diffraction, scanning electron microscopy, ultraviolet-visible light (UV-Vis) spectrophotometry and temperature dependent electrical resistivity measurements. The pyrochlore is observed to have a cubic FCC crystal lattice with lattice parameter of 10.578 angstrom. The planes of the cubic cell are best oriented in the [2 2 2] direction. From the X-ray, the UV-Vis spectrophotometry and the electrical resistivity data analysis, the grain size, strain, dislocation density, optical and thermal energy band gaps, localized energy band tail states and resistivity activation energies are determined and discussed. The pyrochlore is observed to have an optical energy band gap of similar to 3.40 eV. This value corresponds to 365 nm UV light spectra which nominates the neodymium tin oxide pyrochlore ceramics for the use as UV sensors.
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    Article
    Citation - WoS: 4
    Citation - Scopus: 4
    Optical Dynamics at the Au/Znpc Interfaces
    (Univ Fed Sao Carlos, dept Engenharia Materials, 2020) Qasrawi, A. F.; Zyoud, Hadeel M.
    In this work, the optical dynamics and the structural properties of the zinc phthalocyanine which are coated onto 150 nm thick Au substrates are studied by the X-ray diffraction and optical spectrophotometry techniques. The Au/ZnPc interfaces appears to be strongly affected by the large lattice mismatches at the interface. It is observed that the coating ZnPc onto Au substrates increases the light absorbability by 4.7 and 128.2 times in the visible and infrared regions of light, respectively. Au substrates activated the free carrier absorption mechanism in the ZnPc thin films in the infrared range of light. In addition, the transparent Au substrates forced narrowing the energy band gap in both of the Q and B bands. It also increased the dielectric constant value by similar to 3.5 times in the IR range. The enhancements in the optical properties of ZnPc that resulted from the thin Au substrates make the ZnPc more suitable for optoelectronic, nonlinear optical applications and for electromagnetic energy storage in the infrared range of light.
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    Article
    Citation - WoS: 9
    Citation - Scopus: 9
    Indium Slabs Induced Structural Phase Transitions and Their Effects on the Electrical and Optical Properties of Stacked Layers of the Thermally Annealed Cu2o Thin Films
    (Elsevier, 2020) AlGarni, Sabah E.; Qasrawi, A. F.
    In this work, the effects of the structural evolutions caused by the insertion of indium slabs (100 nm) between layers of cupric oxide on the electrical and optical properties are investigated. The stacked layers of Cu2O/Cu2O (CC) which are thermally annealed at 500 degrees C in a vacuum media is observed to comprise both of the CuO (45.9%) and Cu2O (54.1%) phases in its structure. The major structural phase of CuO and Cu2O are monoclinic and orthorhombic, respectively. Insertion of indium slabs which is followed by thermal annealing reduced the content of CuO to 29.2% and enriched the content of Cu2O to 70.8%. The CC samples exhibited structural phase transitions from monoclinic CuO to hexagonal Cu2O in the presence of indium and under thermal annealing. The insertion of indium slabs in the samples increased the crystallite size and enhanced the optical transmittance. It also decreased the microstrain, the defect density and the electrical resistivity. The donor states are shifted deeper below the conduction band edge. The nature of optical transitions also changed from direct allowed to direct forbidden with a decrease in the energy band gap values from 2.05 to 0.85 eV upon indium slabs insertion followed by annealing process.
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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: 19
    Citation - Scopus: 19
    Effect of Indium Nano-Sandwiching on the Structural and Optical Performance of Znse Films
    (Elsevier Science Bv, 2017) Al Garni, S. E.; Qasrawi, A. F.
    In the current study, we attempted to explore the effects of the Indium nanosandwiching on the mechanical and optical properties of the physically evaporated ZnSe thin films by means of X-ray diffractions and ultraviolet spectrophotometry techniques. While the thickness of each layer of ZnSe was fixed at 1.0 mu m, the thickness of the nanosandwiched Indium thin films was varied in the range of 25- 100 nm. It was observed that the as grown ZnSe films exhibits cubic and hexagonal nature of crystallization as those of the ZnSe powders before the film deposition. The cubic phases weighs similar to 70% of the structure. The analysis of this phases revealed that there is a systematic variation process presented by the decreasing of; the lattice constant, compressing strain, stress, stacking faults and dislocation intensity and increasing grain size resulted from increasing the Indium layer thickness in the range of 50-100 nm. In addition, the nanosandwiching of Indium between two layers of ZnSe is observed to enhance the absorbability of the ZnSe. Particularly, at incident photon energy of 2.38 eV the absorbability of the ZnSe films which are sandwiched with 100 nm Indium is increased by 13.8 times. Moreover, increasing the thickness of the Indium layer shrinks the optical energy band gap. These systematic variations in mechanical and optical properties are assigned to the better recrystallization process that is associated with Indium insertion which in turn allows total internal energy redistribution in the ZnSe films through the enlargement of grains. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.