Qasrawı, Atef Fayez Hasan

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Qasrawı, Atef Fayez Hasan

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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Sustainable Development Goals

2

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0

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11

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14

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6

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1

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5

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9

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0

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16

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1

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17

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0

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15

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10

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0

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7

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17

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8

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0

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4

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12

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3

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This researcher does not have a Scopus ID.

This researcher does not have a WoS ID.

Scholarly Output

222

Articles

218

Views / Downloads

639/0

Supervised MSc Theses

0

Supervised PhD Theses

0

WoS Citation Count

1886

Scopus Citation Count

1906

WoS h-index

21

Scopus h-index

21

Patents

0

Projects

0

WoS Citations per Publication

8.50

Scopus Citations per Publication

8.59

Open Access Source

17

Supervised Theses

0

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Journal	Count
Journal of Electronic Materials	15
Crystal Research and Technology	13
physica status solidi (a)	12
Journal of Alloys and Compounds	11
Materials Science in Semiconductor Processing	11

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Scholarly Output Search Results

Now showing 1 - 10 of 27

Citation - WoS: 42
Citation - Scopus: 41
Synthesis and Characterization of Mg₂b_2<
(Pergamon-elsevier Science Ltd, 2005) Qasrawi, AF; Kayed, TS; Mergen, A; Gürü, M
Magnesium borate of the form Mg2B2O5 has been prepared and its structural and thermal properties were studied using X-ray diffraction and differential thermal analysis. An investigation of the electrical and optical properties of Mg2B2O5 system has been carried out. The electrical resistivity of the sample was measured in the temperature range of 170-400 K. The data analysis revealed an extrinsic nature of the conductivity with two impurity levels located at 0.13 and 0.71 eV in the temperature ranges of 170-230 K and 240-400 K, respectively. The optical transmission and reflection was recorded at 300 K in the incident photon energy range of 3.0-6.0 eV. The absorption coefficient data analysis revealed an indirect optical energy band gap of 4.73 eV. In addition, two impurity levels located at 3.43, and 4.49 eV were observed in the absorption spectra. (c) 2005 Elsevier Ltd. All rights reserved.
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.
Citation - WoS: 28
Citation - Scopus: 10
Electrical Conductivity and Hall Mobility in P-Type Tlgase₂ Crystals
(Pergamon-elsevier Science Ltd, 2004) Qasrawi, AF; Qasrawı, Atef Fayez Hasan; Gasanly, NM; Qasrawı, Atef Fayez Hasan; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics Engineering
Systematic dark electrical conductivity and Hall mobility measurements have been carried out in the temperature range of 200-350 K on p-type TlGaSe2 crystals. The analysis of the temperature-dependent electrical conductivity and carrier concentration reveals the extrinsic type of conduction with an acceptor impurity level located at 0.33 eV, and donor and acceptor concentrations of 9.0 x 10(15) and 1.3 x 10(16) cm(-3), respectively. A hole and electron effective masses of 0.520m(0) and 0.325m(0), respectively, with a donor to acceptor compensating ratio of 0.69 are also being identified. The Hall mobility is found to be limited by the hole-phonon short-range interactions scattering with a hole-phonon coupling constant of 0.17. (C) 2004 Elsevier Ltd. All rights reserved.
Citation - WoS: 1
Carrier Transport Properties of Ins Single Crystals
(Wiley-blackwell, 2003) Qasrawi, AF; Gasanly, NM
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 m(0), 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.
Citation - WoS: 11
Citation - Scopus: 13
Fabrication and Characterization of To/Gase Au) Schottky Diodes
(Iop Publishing Ltd, 2006) Qasrawi, AF; Department of Electrical & Electronics Engineering
The optical properties of amorphous GaSe thin films deposited onto tin oxide (TO) coated glass substrates are presented for the purpose of using this material for the fabrication of metal-semiconductor devices. Specifically, the room temperature direct allowed and forbidden transition energy band gaps of glass/TO and glass/TO/GaSe films are estimated and found to exhibit values of 3.95 and 1.95 eV, respectively. The temperature dependence of the energy band gap of the glass/TO/GaSe is also studied in the temperature range of 295 - 450 K by means of optical transmittance and reflectance spectra. This study allowed the identification of the rate of change of the band gap with temperature as -5.0 x 10(-4) eV K-1 and the 0 K energy band gap as 2.1 eV. The above reported optical parameters of the glass/TO/GaSe structure seem to be suitable for semiconductor device production such as solar cell converters, metal - insulator - semiconductor (MIS), metal-oxide-semiconductor (MOS), MOSFET, etc devices. As an application, we have used the glass/TO/GaSe substrate for fabricating Schottky diodes using Ag and Au point contacts. The diodes are characterized by measuring the current (I) - voltage (V) characteristics at room temperature. The I - V curves exhibit rectifying properties. The I-V data analysis in the Schottky region (below 1.0 V) revealed barrier heights of 0.60 and 0.73 eV for Ag and Au point contacts, respectively.
Citation - WoS: 29
Citation - Scopus: 28
Optoelectronical Properties of Polycrystalline Β-Gase Thin Films
(Wiley-v C H verlag Gmbh, 2006) Qasrawi, AF; Ahmad, MMS
Polycrystalline beta-GaSe thin films were obtained by the thermal evaporation of GaSe crystals onto glass substrates kept at 300 degrees C under a pressure of 10(-5) Torr. The transmittance and reflectance of these films was measured in the incident photon energy range of 1.1-3.70 eV. The absorption coefficient spectral analysis in the sharp absorption region revealed a direct allowed transitions band gap of 1.83 eV. The data analysis allowed the identification of the dispersive optical parameters by calculating the refractive index in the wavelength region of 620-1100 nm. In addition, the photocurrent of the samples was studied as function of incident illumination-intensity and temperature. The photocurrent is found to exhibit sublinear and supralinear character above and below 270 K, respectively. The temperature dependent photocurrent data analysis allowed the calculation of photocurrent activation energies as 603, 119 and 45 meV being dominant in the temperature regions of 250-300 K, 180-240 K and 80-160 K, respectively. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Citation - WoS: 6
Citation - Scopus: 8
Temperature and Magnetic Field Effects on the Carrier Density and Hall Mobility of Boron-Doped Tl-Ba Superconductor
(Elsevier Science Sa, 2005) Kayed, TS; Qasrawi, AF
Boron-doped T1-based superconductor was prepared by adding an amount of 1 wt.% B to the Tl1.8Ba2Ca2.2Cu3Ox, compound. The usual solid-state reaction method has been applied under optimum conditions. The X-ray data of the sample show a tetragonal structure with a high ratio of T1-2223 superconducting phase. The sample showed a transition at 125 K and the zero resistance was observed at 120 K. The magnetic field and temperature effects on the normal state electrical resistivity, carrier density, and Hall mobility have been investigated. Both temperature and magnetic field significantly affect the resistivity behavior. The zero field resistivity was found to vary exponentially with temperature with a slope revealing activation energy of 27.5 meV. When the magnetic field is applied, the resistivity varied up-normally in the temperature region of 160-240 K. The temperature dependent carrier concentration calculated from the Hall coefficient data varied linearly with the applied magnetic field. This effect was attributed to the increase in the hole effective mass upon field increment. The temperature-dependent carrier concentration data at several applied fields were analyzed by the single donor-single acceptor model to obtain the values of effective masses. The temperature and magnetic field dependent normal state Hall mobility was found to be limited by the scattering of acoustic phonons. (c) 2005 Elsevier B.V. All rights reserved.
Citation - WoS: 30
Citation - Scopus: 30
Optoelectronic and Electrical Properties of Tlgas₂ Single Crystal
(Wiley-v C H verlag Gmbh, 2005) Qasrawi, AF; Gasanly, NM
The optoelectronic and electrical properties of TIGaS2 single crystals have been investigated by means of room temperature transmittance and reflectance spectral analysis, Hall coefficient, dark electrical resistivity and photocurrent measurements in the temperature range of 200-350 K. The optical data have revealed an indirect and direct allowed transition band gaps of 2.45 and 2.51 eV, an oscillator and dispersion energy of 5.04 and 26.45 eV, respectively, a static dielectric constant of 6.25 and static refractive index of 2.50. The dark Hall coefficient measurements have shown that the crystals exhibit a conductivity type conversion from p-type to n-type at a critical temperature of 315 K. Deep donor and acceptor energy levels of 0.37/0.36 eV and 0.66 eV has been calculated from the temperature dependence of Hall coefficient and resistivity, and photocurrent measurements, respectively. The photocurrent decreases with decreasing temperature. The analysis of the photocurrent data have revealed that, the recombination mechanism is linear and supralinear above and below 290 K, respectively. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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.
Citation - WoS: 28
Citation - Scopus: 27
Photoelectronic and Electrical Properties of Cuin₅s_{8< 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.

Qasrawı, Atef Fayez Hasan

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Sustainable Development Goals

2

ZERO HUNGER

0

Research Products

11

SUSTAINABLE CITIES AND COMMUNITIES

0

Research Products

14

LIFE BELOW WATER

0

Research Products

6

CLEAN WATER AND SANITATION

0

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1

NO POVERTY

0

Research Products

5

GENDER EQUALITY

0

Research Products

9

INDUSTRY, INNOVATION AND INFRASTRUCTURE

0

Research Products

16

PEACE, JUSTICE AND STRONG INSTITUTIONS

1

Research Products

17

PARTNERSHIPS FOR THE GOALS

0

Research Products

15

LIFE ON LAND

0

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10

REDUCED INEQUALITIES

0

Research Products

7

AFFORDABLE AND CLEAN ENERGY

17

Research Products

8

DECENT WORK AND ECONOMIC GROWTH

0

Research Products

4

QUALITY EDUCATION

0

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12

RESPONSIBLE CONSUMPTION AND PRODUCTION

0

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3

GOOD HEALTH AND WELL-BEING

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13

CLIMATE ACTION