Browsing by Author "Gasanova, L."
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Article Citation Count: 3Optical properties of (Ga2Se3)0.75 - (Ga2S3)0.25 single crystals by spectroscopic ellipsometry(Elsevier Science Bv, 2019) Işık, Mehmet; Gasanly, N. M.; Gasanova, L.; Department of Electrical & Electronics EngineeringStructural and optical properties of 75 mol % Ga2Se3 - 25 mol % Ga2S3 system of single crystals were investigated by experimental techniques of x-ray diffraction (XRD), energy dispersive spectroscopy, Raman spectroscopy and ellipsometry. XRD pattern indicated that the studied compound has crystalline nature with cubic structure. Vibrational modes in the crystal were revealed using Raman spectroscopy experiments in the 90-450 cm(-1) frequency range and nine modes were observed in the spectrum. Ellipsometry measurements were utilized in the 1.2-6.2 eV range to get spectral dependencies of optical constants; complex dielectric function, refractive index and extinction coefficient. Under the light of fundamental expressions and models, refractive index and extinction coefficient spectra were analyzed to get various optical parameters of the single crystal.Article Citation Count: 8Spectroscopic ellipsometry investigation of optical properties of β-Ga2S3 single crystals(Elsevier Science Bv, 2018) Işık, Mehmet; Gasanly, N. M.; Gasanova, L.; Department of Electrical & Electronics EngineeringGa2S3 single crystals were studied by x-ray diffraction (XRD), energy dispersive spectroscopy and spectroscopic ellipsometry measurements. XRD pattern of the sample is well-matched with reported hexagonal structure of beta-Ga2S3 . The spectra of real and imaginary parts of complex dielectric function (epsilon = epsilon(1) + epsilon(2)) and refractive index (N = n + ik) were plotted in the 1.2-6.2 eV range according to results of ellipsometric data. The e 2 -spectrum and analyses of absorption coefficient pointed out that studied sample has band gap energy of 2.48 eV which is consistent with that of beta-Ga(2)S(3)2. Critical point energies of beta-Ga2S3 were also reported in the present study.Article Citation Count: 5Thermoluminescence in gallium sesquisulfide single crystals: usual and unusual heating rate dependencies(Elsevier Gmbh, 2018) Işık, Mehmet; Isik, M.; Gasanova, L.; Mahammadov, A.; Gasanly, N.; Department of Electrical & Electronics EngineeringThermoluminescence (TL) experiments were conducted for Ga2S3 crystals to obtain information about trapping parameters. TL measurements were performed from 10 to 300 K with varying heating rates in the range of 0.2-0.8 K/s. Two TL glow peaks centered at 44K (peak A) and 91 K (peak B) were observed at heating rate of beta=0.5 K/s. For peak A, TL intensity decreased whereas that for peak B increased with elevating the heating rates that means anomalous heating rate occurred for peak B. TL glow curves were analyzed using initial rise method to find activation energies of traps. Distribution of trap centers was investigated using T-max - T-stop method. Quasi-continuous distributions with increasing activation energies from 40 to 135 meV and 193 to 460 meV were attributed to trap centers A and B, respectively. (C) 2018 Elsevier GmbH. All rights reserved.