Qasrawı, Atef Fayez Hasan
Loading...
Profile URL
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
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
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Sustainable Development Goals
1NO POVERTY
0
Research Products
2ZERO HUNGER
0
Research Products
3GOOD HEALTH AND WELL-BEING
0
Research Products
4QUALITY EDUCATION
0
Research Products
5GENDER EQUALITY
0
Research Products
6CLEAN WATER AND SANITATION
0
Research Products
7AFFORDABLE AND CLEAN ENERGY
17
Research Products
8DECENT WORK AND ECONOMIC GROWTH
0
Research Products
9INDUSTRY, INNOVATION AND INFRASTRUCTURE
0
Research Products
10REDUCED INEQUALITIES
0
Research Products
11SUSTAINABLE CITIES AND COMMUNITIES
0
Research Products
12RESPONSIBLE CONSUMPTION AND PRODUCTION
0
Research Products
13CLIMATE ACTION
0
Research Products
14LIFE BELOW WATER
0
Research Products
15LIFE ON LAND
0
Research Products
16PEACE, JUSTICE AND STRONG INSTITUTIONS
1
Research Products
17PARTNERSHIPS FOR THE GOALS
0
Research Products
This researcher does not have a Scopus ID.
This researcher does not have a WoS ID.
Scholarly Output
226
Articles
222
Views / Downloads
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
| Journal | Count |
|---|---|
| Crystal Research and Technology | 16 |
| Journal of Electronic Materials | 15 |
| physica status solidi (a) | 12 |
| Materials Science in Semiconductor Processing | 11 |
| Journal of Alloys and Compounds | 11 |
Current Page: 1 / 11
Scopus Quartile Distribution
Competency Cloud
27 results
Scholarly Output Search Results
Now showing 1 - 10 of 27
Article Citation - WoS: 12Citation - Scopus: 12Design and Characterization of Tlinse2 Varactor Devices(Elsevier, 2011) Qasrawi, A. F.; Aljammal, Faten G.; Taleb, Nisreen M.; Gasanly, N. M.TlInSe2 single crystal has been successfully prepared by the Bridgman crystal growth technique. The crystal, which exhibits compositional atomic percentages of 25.4%, 25.2% and 49.4% for TI, In and Se, respectively, is found to be of tetragonal structure with lattice parameters of a=0.8035 and c=0.6883 nm. The crystals were used to design radio frequency sensitive varactor device. The temperature dependence of the current-voltage characteristics of the device allowed the calculation of the room temperature barrier height and ideality factor as 0.87 eV and as 3.2, respectively. Rising the device temperature increased the barrier height and decreased the ideality factor. This behavior was attributed to the current transport across the metal-semiconductor interface. The capacitance of the device is observed to increase with increasing voltage and increasing temperature as well. The temperature activation of the capacitance starts above 82 degrees C with a temperature coefficient of capacitance being 1.08 x 10 (3) K (1). Furthermore, the capacitance of the device was observed to increase with increasing frequency up to a maximum critical frequency of 4.0 kHz, after which the capacitance decreased with increasing frequency. The behavior reflected the ability of maximum amount of charge holding being at a 4.0 kHz. The analysis of the capacitance-voltage characteristics at fixed frequencies reflected a frequency dependent barrier height and acceptors density. The decrease in the barrier height and acceptors density with increasing frequency is mainly due to the inability of the free charge to follow the ac signal. (C) 2011 Elsevier B.V. All rights reserved.Article Citation - WoS: 2Citation - Scopus: 2Properties of Tl4se3< Single Crystals and Characterization of Ag/Tl4< Schottky Barrier Diodes(Elsevier Science Bv, 2010) Qasrawi, A. F.; Gasanly, N. M.The main physical properties of Tl4Se3S single crystals were investigated for the first time. Particularly, the crystal data, Debye temperature, dark electrical resistivity and Hall effect in addition to the temperature dependent current-voltage characteristics and photosensitivity of the Ag/Tl4Se3S Schottky barrier diode were studied. The X-ray diffraction patterns have revealed that the crystal exhibited a single phase of tetragonal structure belonging to the D-4h(18) - 14mcm space group. A Debye temperature of 100 K was calculated using the results of the X-ray diffraction analysis. The dark electrical resistivity and Hall-effect measurements indicated that the samples exhibits p-type conduction with an electrical resistivity, carrier concentration and Hall mobility of 6.20 x 10(3) Omega cm, 1.16 x 10(12) cm(-3) and 873 cm(2) V-1 s(-1), respectively. The crystals were observed to have Schottky diode properties. The Ag/Tl4Se3S Schottky barrier device bias voltage was observed to depend on the crystal direction and on temperature. It was found that the calculated energy barrier height decreased and the diode ideality factor increased with temperature decreasing. The photosensitivity-light intensity dependence of this device was found to be linear reflecting the ability of using it in optoelectronics. (C) 2009 Elsevier B.V. All rights reserved.Article Citation - WoS: 9Citation - Scopus: 9Investigation of the Electrical Parameters of Ag/P-tlgases Schottky Contacts(Elsevier, 2012) Qasrawi, A. F.; Gasanly, N. M.p-type TlGaSeS single crystal was used to fabricate a Schottky device. Silver and carbon metals were used as the Ohmic and Schottky contacts, respectively. The device which displayed wide RF band at 13.200 and narrow band at 62.517 kHz with Q value of 1.4 and of 6.3 x 10(4), respectively, is characterized by means of current (I)-voltage (V), capacitance (C)-voltage characteristics as well as capacitance-frequency (f) characteristics. The device series resistance, ideality factor and barrier height are determined from the I-Vcurve as 35.8 M Omega, 1.2 and 0.74 eV, respectively. The apparent acceptor density and the build in voltage of the device increased with increasing ac signal frequency. The high Q value, observed at 62.517 kHz. indicated a much lower rate of energy loss relative to the stored energy of the device. The energy loss (Q(-1)) is much less than 0.001% of the stored value. The device was tested and found to remain at the same mode of resonance for several hours. It never switched or ceased unless it was tuned off. (c) 2012 Elsevier B.V. All rights reserved.Article Citation - WoS: 9Citation - Scopus: 9Transient and Steady State Photoelectronic Analysis in Tlinse2 Crystals(Pergamon-elsevier Science Ltd, 2011) Qasrawi, A. F.; Gasanly, N. M.The temperature and illumination effects on the transient and steady state photoconductivities of TlInSe2 crystals have been studied. Namely, two recombination centres located at 234 and at 94 meV and one trap center located at 173 meV were determined from the temperature-dependent steady state and transient photoconductivities, respectively. The illumination dependence of photoconductivity indicated the domination of sublinear and supralinear recombination mechanisms above and below 160 K, respectively. The change in the recombination mechanism is attributed to the exchange of roles between the linear recombination at the surface and trapping centres in the crystal, which become dominant as temperature decreases. The transient photoconductivity measurement allowed the determination of the capture coefficient of traps for holes as 3.11 x 10(-22) cm(-2). (C) 2011 Elsevier Ltd. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Hall Mobility and Photoconductivity in Tlgases Crystals(Amer inst Physics, 2013) Qasrawi, A. F.; Gasanly, N. M.In this work, the fundamental properties of the TlGaSeS single crystals are investigated by means of temperature dependent electrical resistivity and Hall mobility. The crystal photo-responsibility as function of illumination intensity and temperature is also tested in the temperature range of 350-160 K. The study allowed the determination of acceptor centers as 230 and 450 meV below and above 260 K, and recombination centers as 181, 363, and 10 meV at low, moderate, and high temperatures, respectively. While the temperature-dependent Hall mobility behaved abnormally, the photoconductivity analysis reflected an illumination intensity dependent recombination center. Namely, the recombination center increased from 10 to 90 meV as the light intensity increased from 27.9 to 76.7 mW cm(-2), respectively. That strange behavior was attributed to the temporary shift in Fermi level caused by photoexcitation. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775577]Article Citation - WoS: 9Citation - Scopus: 9Energy Band Diagram and Current Transport Mechanism in P-mgo/N-ga4<(Ieee-inst Electrical Electronics Engineers inc, 2015) Qasrawi, Atef F.; Gasanly, N. M.A p-n heterojunction made of MgO and Ga4Se3S single crystal has been successfully produced. The current-voltage curve analysis has shown that the current conduction mechanism is mostly governed by the Richardson-Schottky mechanism. The width of the effective interface region of the p-n junction was found to be 3.72x10(-5)cm. The work function and the electron affinity of the Ga4Se3S crystals were also determined as 4.32 and 3.96 eV, respectively. On the other hand, the capacitance-voltage curve analysis, which was carried out in the power range that extends from Bluetooth to WLAN power outputs, reflected a built-in voltage of 0.48 eV and density of noncompensated carriers of 8.2 x 10(16)cm(-3). The device is observed to exhibit a wide range of negative resistance associated with the tunneling of charged particles at reverse biasing down to similar to 1.28 V. At that voltage, when exposed to a He-Ne laser beam of similar to 3 mW, the device reflected a responsivity of similar to 80. The charge storability increased and the I-V characteristics are significantly shifted. These properties are promising because it indicates the applicability of these tunneling devices in optoelectronics.Article Citation - WoS: 7Citation - Scopus: 7Dynamical and Passive Characteristics of the Ag/Tlgases Rf Resonators(Wiley-v C H verlag Gmbh, 2012) Qasrawi, A. F.; Elayyat, S. M. S.; Gasanly, N. M.Ag contacts on the surface of the TlGaSeS single crystals are observed to exhibit Schottky characteristics. The ideality factor of the Ag/ TlGaSeS/Ag device decreased from 5.2 to 1.3 by the reduction of series resistance effect on the I-V characteristics. Cheung's model analysis revealed a series resistance and barrier height of 40.6 KO and 0.32 V, respectively. The device was run on the passive mode by injection with an alternating ac signal of variable frequency in the frequency range of 0-120 MHz and recoding the device capacitance. Several resonance-antiresonance positions in the range of 27-350 KHz were observed. The tangent loss factor of the passive device was observed to decrease with increasing frequency. It exhibited a very low loss value of the order of 10-5 at 120 MHz. Such property is a characteristic of high performance tunable device being suitable as processor clock controller.Article Influence of Photonic Excitations on the Electrical Parameters of Tlins2 Crystals(Wiley-v C H verlag Gmbh, 2010) Qasrawi, A. F.; Gasanly, N. M.The photo-excitation effect on the current transport mechanism in TlInS2 crystals has been studied by means of dark and illuminated conductivity measurements. The temperature-dependent electrical conductivity analysis in the temperature region of 110-340 K revealed the domination of the thermionic emission and the thermally assisted variable range hopping (VRH) of charge carriers above and below 160 K, respectively. Above 160 K, the conductivity activation energies in the dark are found to be 0.28 and 0.15 eV in the temperature regions of 340-240 K and 230-160 K, respectively. In the temperature region of 110-150 K, the dark variable range hopping analysis revealed a density of localized states of 1.99x 10(22) cm(-3)eV(-1), an average hopping distance of 0.53 nm and an average hopping energy of 79.65 meV. When the sample was photo-excited, the values of the conductivity activation energies, the density of localized states near the Fermi level and the average hopping energy were observed to decrease sharply with increasing illumination intensity. On the other hand, the average hopping distance increased with rising illumination intensity. Such behaviours were attributed to the Fermi level shift and/or trap density reduction by electron-hole recombination. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimArticle Citation - WoS: 7Citation - Scopus: 6Temperature-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.Article Citation - WoS: 4Citation - Scopus: 4Mixed Conduction and Anisotropic Single Oscillator Parameters in Low Dimensional Tlinse2 Crystals(Elsevier Science Sa, 2013) Qasrawi, A. F.; Gasanly, N. M.Due to the importance of the TlInSe2 crystal as neutron and gamma-ray detectors, its electrical and dispersive optical parameters have been investigated. Particularly, the anisotropic current conduction mechanism in the temperature region of 100-350 K and the room temperature anisotropic dispersive optical properties were studied by means of electrical conductivity and optical reflectance, respectively. It has been shown that the mixed conduction is the most dominant transport mechanism in the TlInSe2 crystals. Particularly, when the electric field is applied perpendicular to the crystal's c-axis, the main dominant current transport mechanism is due to the mixed conduction and the variable range hopping above and below 160 K, respectively. When the electric field is applied parallel to the crystal's c-axis, the electrical conductivity is dominated by the thermionic emission, mixed conduction and variable range hopping at high, moderate and low temperatures, respectively. The optical reflectivity analysis in the wavelength range 210-1500 nm revealed a clear anisotropy effect on the dispersive optical parameters. Particularly, the static refractive index, static dielectric constant, dispersion energy and oscillator energy exhibited values of 2.50, 6.24, 20.72 eV and 3.96 eV, and values of 3.05, 9.33, 39.27 eV and 4.72 eV for light propagation parallel and perpendicular to the crystal's c-axis, respectively. Moreover, the frequency dependence of the dielectric constant, epsilon(omega), reflected strong dielectric anisotropy that exhibit maximum epsilon(omega) value of 38.80 and 11.40 at frequencies of 11.07 x 10(14) Hz for light propagation parallel and perpendicular to the crystal's c-axis, respectively. The anisotropy in the epsilon(omega) makes the TlInSe2 crystals attractive to be used as nonvolatile static memory devices. (C) 2013 Elsevier B.V. All rights reserved.
- «
- 1 (current)
- 2
- 3
- »