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Article Defect Characterization of Ga4se3< Layered Single Crystals by Thermoluminescence(indian Acad Sciences, 2016) Isik, M.; Delice, S.; Gasanly, N.Trapping centres in undoped Ga4Se3S single crystals grown by Bridgman method were characterized for the first time by thermoluminescence (TL) measurements carried out in the low-temperature range of 15-300 K. After illuminating the sample with blue light (similar to 470 nm) at 15 K, TL glow curve exhibited one peak around 74 K when measured with a heating rate of 0.4 K/s. The results of the various analysis methods were in good agreement about the presence of one trapping centre with an activation energy of 27 meV. Analysis of curve fitting method indicated that mixed order of kinetics dominates the trapping process. Heating rate dependence and distribution of the traps associated with the observed TL peak were also studied. The shift of peak maximum temperature from 74 to 113 K with increasing rate from 0.4 to 1.2 K/s was revealed. Distribution of traps was investigated using an experimental technique based on cleaning the centres giving emission at lower temperatures. Activation energies of the levels were observed to be increasing from 27 to 40 meV by rising the stopping temperature from 15 to 36 K.Article Citation - WoS: 28Citation - Scopus: 10Electrical 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 EngineeringSystematic 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.Article Citation - WoS: 14Citation - Scopus: 13Enhancement of Electrical Performance of Znse Thin Films Via Au Nanosandwiching(Sciendo, 2020) Qasrawi, A. F.; Taleb, Maram F.In this work, we report the effect of sandwiching of Au nanosheets on the structural and electrical properties of ZnSe thin films. The ZnSe films which are grown by the thermal evaporation technique onto glass and yttrium thin film substrates exhibit lattice deformation accompanied with lattice constant extension, grain size reduction and increased defect density upon Au nanosandwiching. The temperature dependent direct current conductivity analysis has shown that the 70 nm thick Au layers successfully increased the electrical conductivity by three orders of magnitude without causing degeneracy. On the other hand, the alternating current conductivity studies in the frequency domain of 10 MHz to 1800 MHz have shown that the alternating current conduction in ZnSe is dominated by both of quantum mechanical tunneling and correlated barrier hopping of electrons over the energy barriers formed at the grain boundaries. The Au nanosheets are observed to increase the density of localized states near Fermi level and reduce the average hopping energy by similar to 5 times. The conductivity, capacitance, impedance and reflection coefficient spectral analyses have shown that the nanosandwiching of Au between two layers of ZnSe makes the zinc selenide more appropriate for electronic applications and for applications which need microwave cavities.Article Citation - WoS: 2Citation - Scopus: 2Thermoluminescence Dose Response and Kinetic Parameters of Gd-Doped Zno Nanoparticles(Iop Publishing Ltd, 2024) Isik, M.; Yildirim, T.; Guner, M.; Gasanly, N. M.This study investigates the thermoluminescence (TL) properties of undoped and gadolinium (Gd)-doped zinc oxide (ZnO) nanoparticles synthesized via sol-gel method. The crystal structure of both synthesized nanoparticles was determined as hexagonal from x-ray diffraction pattern. The TL curve of undoped ZnO nanoparticles reveals two distinct peaks at 400.5 and 479.2 K, each associated with trap centers featuring activation energies of 0.84 and 1.05 eV. TL curve of the Gd:ZnO introduced three peaks associated with trap centers at 1.10, 1.18, and 1.25 eV. Notably, the absence of the 0.84 eV trap center in Gd-doped ZnO implies a modification in the defect structure. Considering the effect of Gd-doping on the band structure and potential minor errors in the analysis results, it was stated that the traps at 1.05 and 1.10 eV levels belonged to the same defect center. Dose-dependent investigations for undoped and Gd-doped ZnO nanoparticles reveal linear behaviors in the TL response, highlighting their potential for dosimetric applications. Photoluminescence spectra of both compounds exhibited emission peaks around 455 and 577 nm, which were associated with native defect centers.Article Citation - WoS: 2Citation - Scopus: 2Investigation of Defect Levels in Bi12sio20< Single Crystals by Thermally Stimulated Current Measurements(Iop Publishing Ltd, 2021) Isik, M.; Delice, S.; Gasanly, N. M.Bi12SiO20 (BSO) single crystal belongs to the sillenite semiconducting family known as defective compounds. The present paper investigates the defect centers in BSO grown by Czochralski method by means of thermally stimulated current (TSC) measurements performed in the 10-260 K range. The TSC glow curve obtained at heating rate of beta = 0.1 K s(-1) presented several peaks associated with intrinsic defect centers. The activation energies of defect centers were revealed as 0.09, 0.15, 0.18, 0.22, 0.34, 0.70 and 0.82 eV accomplishing the curve fit analyses method. The peak maximum temperatures and orders of kinetics of each deconvoluted peak were also determined as an outcome of fitting process. TSC experiments were expanded by making the measurements at various heating rates between 0.1 and 0.3 K s(-1) to get information about the heating rate dependent peak parameters.Article Citation - WoS: 17Citation - Scopus: 17Trap Distribution in Tlins2 Layered Crystals From Thermally Stimulated Current Measurements(Korean Physical Soc, 2008) Isik, M.; Goksen, K.; Gasanly, N. M.; Ozkan, H.We have carried out thermally stimulated current (TSC) measurements with the current flowing along the layer on as-grown TlInS2 layered single crystals in the low temperature range 10 - 110 K with different heating rates of 0.1 - 1.5 K/s. Experimental evidence was found for the presence of two shallow electron trapping centers with activation energies of 12 and 14 meV. Their capture cross sections have been determined as 2.2 x 10(-23) and 7.1 x 10(-25) cm(2), respectively. It was concluded that retrapping in these centers is negligible, which was confirmed by the good agreement between the experimental results and the theoretical predictions of the model that assumed slow retrapping. An exponential distribution of electron traps was revealed from the analysis of the TSC data obtained at different light excitation temperatures. This experimental technique provided a value of 27 meV/decade for the trap distribution. The parameters of the monoclinic unit cell were determined by studying the X-ray powder diffraction.Article Citation - WoS: 2Citation - Scopus: 2Thermoluminescence Characteristics of Tl4gain3< Layered Single Crystals(Taylor & Francis Ltd, 2014) Delice, S.; Isik, M.; Gasanly, N. M.The properties of trapping centres in - as grown - Tl4GaIn3S8 layered single crystals were investigated in the temperature range of 10-300K using thermoluminescence (TL) measurements. TL curve was analysed to characterize the defects responsible for the observed peaks. Thermal activation energies of the trapping centres were determined using various methods: curve fitting, initial rise and peak shape methods. The results indicated that the peak observed in the low-temperature region composed of many overlapped peaks corresponding to distributed trapping centres in the crystal structure. The apparent thermal energies of the distributed traps were observed to be shifted from similar to 12 to similar to 125meV by increasing the illumination temperature from 10 to 36K. The analysis revealed that the first-order kinetics (slow retrapping) obeys for deeper level located at 292meV.Article Citation - WoS: 6Citation - Scopus: 7Characteristic Features of Thermoluminescence in Neodymium-Doped Gallium Sulfide(Wiley, 2018) Guler, I.; Isik, M.; Ahmedova, F.; Guseinov, A.; Gasanly, N.The thermoluminescence (TL) of neodymium-doped gallium sulfide (GaS:Nd) single crystals was measured from 10 K to room temperature with various heating rates between 0.2 and 1.0 K/sec. Two peaks centered at 70.9 K and 116.0 K were observed when using a heating rate of 0.8 K/sec. Initial rise and curve fitting methods were used to obtain information on trap activation energies. Activation energies of 94 and 216 meV were found for two analyzable peaks. The heating rate dependencies of TL intensities revealed that one of the observed peaks showed normal behavior according to the one trap-one recombination model, whereas the other model showed anomalous heating rate behavior. TL experiments were also carried out at different illumination temperatures from 10 to 32 K; maximum peak temperature remained almost the same at various illumination temperatures. This behavior indicated that the revealed trapping centers are single, discrete levels. The TL glow curves of undoped GaS crystals were also investigated and the effect of Nd doping on the TL characteristics of crystals is discussed in the manuscript.
