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Citation - WoS: 7
Citation - Scopus: 6
Temperature-Dependent Structural Transition, Electronic Properties and Impedance Spectroscopy Analysis of Tl₂ingas_{4< 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.
Citation - WoS: 13
Citation - Scopus: 14
Linear and Nonlinear Optical Properties of Bi12geo20 Single Crystal for Optoelectronic Applications
(Elsevier Sci Ltd, 2023) Isik, M.; Gasanly, N. M.
The present paper aims at presenting linear and nonlinear optical properties of Bi12GeO20 single crystals grown by Czochralski method. Transmission and reflection measurements were performed in the 400-1000 nm region. The recorded spectra were analyzed considering well-known optical models. Spectral dependencies of absorption coefficient, skin depth, refractive index, real and imaginary components of dielectric function were presented. The analyses performed on absorption coefficient showed direct bandgap and Urbach energies as 2.56 and 0.22 eV, respectively. The first-and third-order nonlinear susceptibilities and nonlinear refractive index of the crystal were also reported in the present work. The results of the present paper would provide valuable information for optoelectronic device applications of Bi12GeO20.
Citation - WoS: 22
Citation - Scopus: 22
Optical Properties of Tlins₂ Layered Single Crystals Near the Absorption Edge
(Springer, 2006) Qasrawi, A. F.; Gasanly, N. M.
The sample thickness effect on the optical properties of TlInS2 layered crystals has been investigated at room temperature. The absorption coefficient of the samples calculated from the experimental transmittance and reflectance in the photon energy range of 1.10-3.10 eV has two absorption regions. The first is a long-wavelength region of 1.16-1.28 eV. The second region lies above 2.21 eV with a thickness-dependent indirect band gap. The energy gap decreases from 2.333 to 2.255 eV as the sample thickness increases from 27 to 66 mu m. The differential spectra of absorption coefficient demonstrates the existence of a thickness-dependent impurity level being lowered from 2.360 to 2.307 eV as sample thickness increases from 27 to 66 mu m. (c) 2006 Springer Science + Business Media, Inc.
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: 3
Citation - Scopus: 4
Optical Properties of Cu₃in_{5< Single Crystals by Spectroscopic Ellipsometry}
(Elsevier Gmbh, 2018) Isik, M.; Nasser, H.; Ahmedova, F.; Guseinov, A.; Gasanly, N. M.
Cu3In5S9 single crystals were investigated by structural methods of x-ray diffraction and energy dispersive spectroscopy and optical techniques of ellipsometry and reflection carried out at room temperature. The spectral dependencies of optical constants; dielectric function, refractive index and extinction coefficient, were plotted in the range of 1.2-6.2 eV from ellipsometric data. The spectra of optical constants obtained from ellipsometry analyses and reflectance spectra presented a sharp change around 1.55 and 1.50 eV, respectively, which are associated with band gap energy of the crystal. The critical point (interband transition) energies were also found from the analyses of second-energy derivative of real and imaginary components of dielectric function. The analyses indicated the presence of four critical points at 2.73, 135, 4.04 and 4.98 eV.
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: 10
Citation - Scopus: 10
Determination of Mechanical Properties of Bi₁₂tio_{20< Crystals by Nanoindentation}
(Elsevier Sci Ltd, 2022) Isik, M.; Gasanly, N. M.; Rustamov, F. A.
Bi12TiO20 (BTO) single crystal was grown by Czochralski method and investigated mechanically by nano-indentation measurements. X-ray diffraction pattern of the crystal presented one intensive peak around 37.95 degrees associated with (330) plane of cubic crystalline structure. Nanoindentation experiments were performed at various loads between 5 and 100 mN. Hardness and Young's modulus of the crystal were determined by Oliver-Pharr method. The hardness-load dependency exhibited behavior of indentation size effect. True hardness value of BTO crystal was revealed as 4.4 GPa. Young's modulus decreased with increase of load and load-independent Young's modulus was found around 93 GPa at high loads. The load-dependent elastic and plastic deformation components were calculated and it was observed that the dominant component in BTO single crystal is plastic deformation at the applied loads. The present paper reports for the first time the mechanical characteristics of the BTO single crystal by carrying out nanoindentation experiments.
Citation - WoS: 2
Citation - Scopus: 2
Trap Distribution in Agin₅s_{8< Single Crystals: Thermoluminescence Study}
(Pergamon-elsevier Science Ltd, 2018) Delice, S.; Işık, Mehmet; Isik, M.; Gasanly, N. M.; Işık, Mehmet; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics Engineering
Distribution of shallow trap levels in AgIn5S8 crystals has been investigated by thermoluminescence (TL) measurements performed below room temperature (10-300 K). One broad TL peak centered at 33 K was observed as constant heating rate of 0.2 K/s was employed for measurement. The peak shape analysis showed that the TL curve could consist of several individual overlapping TL peaks or existence of quasi-continuous distributed traps. Therefore, TL experiments were repeated for different stopping temperatures (T-stop) between 10 and 34 K with constant heating rate of 0.2 K/s to separate the overlapping TL peaks. The E-t vs T-stop indicated that crystal has quasi-continuously distributed traps having activation energies increasing from 13 to 41 meV. Heating rate effect on trapped charge carriers was also investigated by carrying out the TL. experiments with various heating rates between 0.2 and 0.6 K/s for better comprehension of characteristics of existed trap levels. Analyses indicated that the trap levels exhibited the properties of anomalous heating rate behavior which means the TL intensity and area under the TL peak increase with increasing heating rate.
Citation - WoS: 19
Citation - Scopus: 20
Optical characteristics of Bi₁₂SiO₂₀ single crystals by spectroscopic ellipsometry
(Elsevier Sci Ltd, 2020) Isik, M.; Delice, S.; Nasser, H.; Gasanly, N. M.; Darvishov, N. H.; Bagiev, V. E.
Structural and optical characteristics of Bi12SiO20 single crystal grown by the Czochralski method were investigated by virtue of X-ray diffraction (XRD) and spectroscopic ellipsometry measurements. XRD analysis indicated that the studied crystal possesses cubic structure with lattice parameters of a = 1.0107 nm. Spectral dependencies of several optical parameters like complex dielectric constant, refractive index, extinction and absorption coefficients were determined using ellipsometry experiments performed in the energy region of 1.2-6.2 eV. The energy band gap of Bi12SiO20 crystals was found to be 3.25 eV by utilizing absorption coefficient analysis. Moreover, critical point energies were calculated as 3.54, 4.02, 4.82 and 5.58 eV from analyses of the second energy derivative spectra of the complex dielectric constant.

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