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Citation - WoS: 5
Citation - Scopus: 5
Low-Temperature Thermoluminescence in Layered Structured Ga_0.75in_{0.25< Single Crystals}
(Elsevier Science Sa, 2012) Isik, M.; Bulur, E.; Gasanly, N. M.
Defect centers in Ga0.75In0.25Se single crystals have been studied performing the thermoluminescence measurements in the temperature range of 10-300 K. The observed glow curves were analyzed using curve fitting, initial rise, and different heating rate methods to determine the activation energies of the defect centers. Thermal cleaning process has been applied to decompose the overlapped curves. Four defect centers with activation energies of 9, 45,54 and 60 meV have been found as a result of the analysis. The capture cross sections and attempt-to-escape frequencies of the defect centers were also found using the curve fitting method under the light of theoretical predictions. The first order kinetics for the observed glow curve was revealed from the consistency between the theoretical predictions for slow retrapping and experimental results. Another indication of negligible retrapping was the independency of peak position from concentration of carriers trapped in defect levels. (C) 2012 Elsevier B.V. All rights reserved.
Citation - WoS: 10
Citation - Scopus: 11
Low Temperature Thermoluminescence of Gd₂o_{3< Nanoparticles Using Various Heating Rate and t_{max< - t_{exc< Methods}}}
(Elsevier, 2019) Delice, Serdar; Isik, Mehmet; Gasanly, Nizami M.
Thermoluminescence (FL) measurements for Gd2O3 nanoparticles were carried out for various heating rates between 0.3 and 0.8 K/s at low temperatures (10-280 K). TL spectrum exhibited two observable and one faint peaks in the temperature region of 10-100 K, and four peaks in the temperature region of 160-280 K. Heating rate analysis was achieved to understand the behaviors of trap levels. It was seen that the peak maximum temperatures and TL intensities of all peaks increase with increasing heating rate. This behavior was ascribed to anomalous heating rate effect. T-max - T(exc )analysis was accomplished for TL, peaks at relatively higher temperature region to reveal the related traps depths. T-max - T-exc plot presented a staircase structure indicating that the TL glow curve is composed of well separated glow peaks. Mean activation energies of trapping centers corresponding to these separated peaks were found as 0.43, 0.50, 0.58 and 0.80 eV.
Citation - WoS: 5
Citation - Scopus: 5
Determination of Trapping Parameters of Thermoluminescent Glow Peaks of Semiconducting Tl₂ga_{2< Crystals}
(Pergamon-elsevier Science Ltd, 2015) Isik, M.; Yildirim, T.; Gasanly, N. M.
Thermoluminescence (TL) properties of Tl2Ga2S3Se layered single crystals were researched in the temperature range of 290-770 K. U glow curve exhibited two peaks with maximum temperatures of similar to 373 and 478 K. Curve fitting, initial rise and peak shape methods were used to determine the activation energies of the trapping centers associated with these peaks. Applied methods were in good agreement with the energies of 780 and 950 meV. Capture cross sections and attempt-to-escape frequencies of the trapping centers were reported. An energy level diagram showing transitions in the band gap of the crystal was plotted under the light of the results of the present work and previously reported papers on photoluminescence, thermoluminescence and thermally stimulated current measurements carried out below room temperature. (C) 2015 Elsevier Ltd. All rights reserved.
Citation - WoS: 7
Citation - Scopus: 7
Trapping Centers and Their Distribution in Tl₂ga_{2< Layered Single Crystals}
(Pergamon-elsevier Science Ltd, 2009) Isik, M.; Gasanly, N. M.
Thermally stimulated current (TSC) measurements with current flowing perpendicular to the layers were carried out on Tl2Ga2Se3S layered single crystals in the temperature range of 10-260K. The experimental data were analyzed by using different methods, such as curve fitting, initial rise and isothermal decay methods. The analysis revealed that there were three trapping centers with activation energies of 12, 76 and 177 meV. It was concluded that retrapping in these centers was negligible, which was confirmed by the good agreement between the experimental results and the theoretical predictions of the model that assumes slow retrapping. The capture cross section and the concentration of the traps have been also determined. An exponential distribution of electron traps was revealed from the analysis of the TSC data obtained at different light illumination temperatures. This experimental technique provided values of 10 and 88 meV/decade for the traps distribution related to two different trapping centers. (C) 2009 Elsevier Ltd. All rights reserved.
Citation - WoS: 14
Citation - Scopus: 14
Low Temperature Thermoluminescence Behaviour of Y₂o_{3< Nanoparticles}
(Elsevier, 2019) Delice, S.; Isik, M.; Gasanly, N. M.
Y2O3 nanoparticles were investigated using low temperature thermoluminescence (TL) experiments. TL glow curve recorded at constant heating rate of 0.4 K/s exhibits seven peaks around 19, 62, 91, 115, 162, 196 and 215 K. Activation energies and characteristics of traps responsible for observed curves were revealed under the light of results of initial rise analyses and T-max-T-stop experimental methods. Analyses of TL curves obtained at different stopping temperatures resulted in presence of one quasi-continuously distributed trap with activation energies increasing from 18 to 24 meV and six single trapping centers at 49, 117, 315, 409, 651 and 740 meV. Activation energies of all revealed centers were reported in the present paper. Structural characterization of Y2O3 nanoparticles was accomplished using X-ray diffraction and scanning electron microscopy measurements. (C) 2019 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.
Citation - WoS: 5
Citation - Scopus: 5
Identification of Shallow Trap Centers in Inse Single Crystals and Investigation of Their Distribution: a Thermally Stimulated Current Spectroscopy
(Elsevier, 2024) Isik, M.; Gasanly, N. M.
Identification of trap centers in semiconductors takes great importance for improving the performance of electronic and optoelectronic devices. In the present study, we employed the thermally stimulated current (TSC) method within a temperature range of 10-280 K to explore trap centers in InSe crystal-a material with promising applications in next-generation devices. Our findings revealed the existence of two distinct hole trap centers within the InSe crystal lattice located at 0.06 and 0.14 eV. Through the leveraging the T-stop method, we offered trap distribution parameters of revealed centers. The results obtained from the experimental methodology employed to investigate the distribution of trap centers indicated that one of the peaks extended between 0.06 and 0.13 eV, while the other spanned from 0.14 to 0.31 eV. Notably, our research uncovers a remarkable variation in trap density, spanning one order of magnitude, for every 10 and 88 meV of energy variation. The results of our research present the characteristics of shallow trap centers in InSe, providing important information for the design and optimization of InSe-based optoelectronic devices.
Citation - WoS: 3
EFFECT OF Y, Au AND YAu NANOSANDWICHING ON THE STRUCTURAL, OPTICAL AND DIELECTRIC PROPERTIES OF ZnSe THIN FILMS
(Natl inst R&d Materials Physics, 2019) Qasrawi, A. F.; Taleb, M. F.
In this article, we report the effects of insertion of yttrium, gold and yttrium-gold (YAu) metallic nano-slabs on the structural, optical and dielectric properties of ZnSe thin films. The ZnSe thin films which are prepared by the thermal evaporation technique under vacuum pressure of 10-5 mbar exhibit hexagonal structure. While the insertion of the 70 nm thick Y layers does not alter the lattice parameters and stress values, the Au and YAu layers increased the lattice parameters along the a- and c-axes and decreased the stress values. In addition, the insertion of these metallic layers slightly alters the value of the energy band gap and increases the width of the interbands. The light absorbability are increased by 1.4, 2.0 and 2.4 times upon insertion of Y, Au and YAu, slabs, respectively. On the other hand, the dielectric and optical conductivity analyses has shown that the use of the YAu stacked metal layers increases the real part of the dielectric constant, the optical conductivity, the drift mobility and extended the plasmon frequency range from 35.1 to 254.0 (Omega cm)(-1), from 1098 to 1766 cm(2)/vs and from 0.94-3.11 GHz to 2.13-4.83 GHz, respectively. The insertion of the two stacked metallic layers between two layers of ZnSe makes the ZnSe more appropriated for thin film transistor technology.
Citation - WoS: 6
Citation - Scopus: 6
Gold and Ytterbium Interfacing Effects on the Properties of the Cdse/Yb Nanosandwiched Structures
(Elsevier Science Bv, 2018) Alharbi, S. R.; Qasrawi, A. F.
Owing to the performance of the CdSe as an optoelectronic material used for the production of quantum dots, photosensors and wave traps we here, in this article, report the enhancements in structural and electrical properties that arises from the nanosandwiching of a 40 nm thick Yb film between two films of CdSe (CYbC-40). The CdSe films which were deposited onto glass, Yb and Au substrates are characterized by X-ray diffraction, temperature dependent electrical conductivity and impedance spectroscopy measurements in the frequency range of 10-1800 MHz. The analysis of the XRD patterns have shown that the glass/CdSe/Yb/CdSe films exhibit larger grain size and lower strain, defect density and lower stacking faults compared to the not sandwiched CdSe. In addition, it was observed that the Yb shifts the donor states of the n-type CdSe from 0.44 to 0.29 eV leading to a modification in the built in voltage of the material. On the other hand, the design of the energy band diagram has shown the ability of the formation of the Au/CYbC-40/Yb as Schottky (SB) and the Au/CYbC-40/Au as back to back Schottky barriers (BBSB). While the SB device show low band pass filter characteristics, the BBSB device performed as band stop filters. The BBSB device exhibited negative capacitance effects with filtering features that reveal a return loss of 42 dB at similar to 1440 MHz.
Citation - WoS: 9
Citation - Scopus: 9
Thermally Stimulated Current Measurements in Undoped Ga₃inse_{4< Single Crystals}
(Pergamon-elsevier Science Ltd, 2011) Isik, M.; Işık, Mehmet; Gasanly, N. M.; Işık, Mehmet; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics Engineering
The trap levels in nominally undoped Ga3InSe4 crystals were investigated in the temperature range of 10-300 K using the thermally stimulated currents technique. The study of trap levels was accomplished by the measurements of current flowing along the c-axis of the crystal. During the experiments we utilized a constant heating rate of 0.8 K/s. Experimental evidence is found for one hole trapping center in the crystal with activation energy of 62 meV. The analysis of the experimental TSC curve gave reasonable results under the model that assumes slow retrapping. The capture cross-section of the trap was determined as 1.0 x 10(-25) cm(2) with concentration of 1.4 x 10(17) cm(-3). (C) 2011 Elsevier Ltd. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
Shallow Trapping Centers in Bi12geo20 Single Crystals by Thermally Stimulated Current Measurements
(Elsevier, 2022) Delice, S.; Isik, M.; Gasanly, N. M.
Bi12GeO20 single crystals were investigated by thermally stimulated current (TSC) experiments performed in the temperature range of 10-290 K. Recorded TSC glow curve exhibited six distinctive peaks with maxima at around 90, 105, 166, 209, 246, 275 K. The analyses of the obtained glow curve were accomplished by curve fitting and initial rise methods. The analysis results were in good agreement that the TSC peaks appeared in the glow curve due to existence of trapping levels with activation energies of 0.10, 0.18, 0.23, 0.53, 0.68 and 0.73 eV. These trapping levels were estimated to be hole traps above valence band. The heating rate dependent TSC glow curves were also obtained for various rates between 0.30 and 0.45 K/s. The changes of TSC intensity, peak maximum temperature and full-widths-half-maximum values with heating rates were studied in detail. TSC intensity decreased and peak maximum temperature increased with increasing heating rate. Determination of defects and trapping/stimulation mechanism of those are significant for technological applications since local states in these materials take critical role for device performance.

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