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Citation - WoS: 1
Citation - Scopus: 1
Hole-Polar Phonon Interaction Scattering Mobility in Chain Structured Tlse_0.75s_{0.25< 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
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
Citation - WoS: 9
Citation - Scopus: 9
Operating Frequency Calculation of a Shorting Pin-Loaded Etma
(Wiley-blackwell, 2012) Aydin, Elif; Can, Sultan
This article presents the calculation of upper and lower operating frequencies with the expressions of effective side length, effective permittivity, and correction factor to develop accurate lower and upper operating frequencies of a single feed, a shorting pin-loaded equilateral triangular patch, that is, analyzed through a cavity model. To insert permittivity and shorting pin position effects correction factor expressions are determined empirically for both upper and lower frequencies. The various positions of the shorting pin, substrate thickness and side length properties are considered by calculating both upper and lower frequencies. The results from this study are compared with research in the literature comprising results from both experimental and transmission line models. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:14321435, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26838
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: 55
Citation - Scopus: 59
The Development of Ring Rolling Technology - Part 2: Investigation of Process Behaviour and Production Equipment
(Wiley-blackwell, 2005) Allwood, JM; Tekkaya, AE; Stanistreet, TF
This is the continuation of a thorough survey of work on ring rolling published in the English and German languages up to 2004 [see No. 2/3, p. 111-120]: The methods used to investigate the process are reviewed, separated into experimental and theoretical categories; the insights gained from these investigations are organised according to the challenges identified at the outset; developments in the control and operation of the process are described. Having given a set of ideal targets for the process, the state of current knowledge about ring rolling is assessed in order to predict likely developments: process modelling capability is nearly able to predict rolling behaviour for a complete cycle with sufficient accuracy to allow effective use of models for design of rolling schedules and preforms; analysis of material behaviour is relatively mature for steel rings, but has scope for significant extension for titanium and aluminium alloys and composites; design choices that seek to extend the flexibility of the process have had some exploration, but could be extended.
Citation - WoS: 1
Citation - Scopus: 3
Calculation of Resonant Frequencies of a Shorting Pin-Loaded Etma With Ann
(Wiley-blackwell, 2014) Can, Sultan; Kapusuz, Kamil Yavuz; Aydin, Elif
[No Abstract Available]
Citation - WoS: 3
Citation - Scopus: 3
Characterization of Ag/Tlinse_{2< Structure}
(Wiley-blackwell, 2011) Qasrawi, A. F.; Gasanly, N. M.
In this work, the current voltage characteristics of Ag/TlInSe2/Ag and In/TlInSe2/In structures, the incident light intensity and time dependencies of photocurrent as well as the response time-illumination intensity dependence of Ag/TlInSe2/Ag structures have been studied. For bias voltages larger than 1200. and 4.0 V, the current injection was found to be space charge limited and was assigned to the existing of deep and shallow hole traps being located at 210 and 16 meV for Ag and In-contacted samples, respectively. While indium-contacted samples show S-shaped I-V dependence above bias voltage of 10.0V, silver contacted samples does not show this behavior even at 200.0 V. For the Ag/TlInSe2/Ag structure, photocurrent was observed to exhibit stable values in a very short period of time. The device response time decreases with increasing illumination intensity, it exhibits a value of 0.13 s at incident light intensity of 53.6 mW cm(-2). The decrement in response time with increasing illumination intensity is associated with an increment in photocurrent at the same ratio. The ohmic behavior up to high voltages (120 V), the fast response time and the large spatial photocurrent make the Ag/TlInSe2/Ag structure promising IR detectors. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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