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Citation - WoS: 5
Citation - Scopus: 5
Dispersive Optical Constants of Tl₂ingase_{4< Single Crystals}
(Iop Publishing Ltd, 2007) Qasrawi, A. F.; Gasanly, N. M.
The structural and optical properties of Bridgman method grown Tl2InGaSe4 crystals have been investigated by means of room temperature x-ray diffraction, and transmittance and reflectance spectral analysis, respectively. The x-ray diffraction technique has shown that Tl2InGaSe4 is a single phase crystal of a monoclinic unit cell that exhibits the lattice parameters of a = 0.77244 nm, b = 0.64945 nm, c = 0.92205 nm and beta = 95.03 degrees . The optical data have revealed an indirect allowed transition band gap of 1.86 eV. The room temperature refractive index, which was calculated from the reflectance and transmittance data, allowed the identification of the dispersion and oscillator energies, static dielectric constant and static refractive index as 28.51 and 3.45 eV, 9.26 and 3.04, respectively.
Citation - WoS: 3
Citation - Scopus: 2
Performance Enhancement of Silicon Photodiodes Through the Integration of Green Synthesized Reduced Graphene Oxide Variants
(Iop Publishing Ltd, 2024) Yildiz, D. E.; Sürücü, Özge; Surucu, O.; Balaban, H. Mert; Bilici, I; Yildirim, M.; Sürücü, Özge; Electrical-Electronics Engineering; Electrical-Electronics Engineering
This study examines the potential of enhancing the optoelectronic properties of silicon photodiodes by producing and analyzing heterostructures that incorporate reduced graphene oxide (rGO) synthesized with silicon using different reduction methods. Graphene oxide (GO) was manufactured utilizing an enhanced Hummers' method. Subsequently, reduced graphene oxides (rGOs) were made by chemical and thermal reduction processes, which are considered ecologically friendly. The use of ascorbic acid to produce ascorbic acid-reduced graphene oxide (ArGO) and thermal processing to produce thermally reduced graphene oxide (TrGO) have significantly contributed to the development of high-performance photodiode technology. The electrical properties were carefully assessed under different levels of light, revealing the substantial impact of integrating reduced graphene oxides (rGOs) on the performance of the diodes. Comparing ArGO/Si, TrGO/Si, and GO/Si heterostructures shows that customized rGO has the potential to greatly influence the responsivity and efficiency of Si-based optoelectronic devices, making a significant contribution to photodiode technology.
Citation - WoS: 20
Citation - Scopus: 20
Properties of the P_c(4312) pentaquark and its bottom partner
(Iop Publishing Ltd, 2021) Azizi, K.; Sarac, Y.; Sundu, H.
We present an analysis of the newly observed pentaquark P-c(4312)(+) to shed light on its quantum numbers. To do that, the QCD sum rules approach is used. The measured mass of this particle is close to the Sigma D-++(c)- threshold and has a small width, which supports the possibility of its being a molecular state. We consider an interpolating current in a molecular form and analyze both the positive and negative parity states with spin-. We also consider the bottom counterpart of the state with similar molecular form. Our mass result for the charm pentaquark state supports that the quantum numbers of the observed state are consistent with J(P) = 1/2(-).
Citation - WoS: 3
Citation - Scopus: 3
Optoelectronic Properties of Ga₄se_{3< Single Crystals}
(Iop Publishing Ltd, 2008) Qasrawi, A. F.; Gasanly, N. M.; Ilaiwi, K. F.
The optoelectronic properties of Bridgman method-grown Ga(4)Se(3)S single crystals have been investigated by means of room temperature electrical resistivity, temperature-dependent photosensitivity and temperature-dependent optical absorption. The photosensitivity was observed to increase with decreasing temperature, the illumination dependence of which was found to exhibit monomolecular recombination in the bulk at 300 K. The absorption coefficient, which was calculated in the incident photon energy range of 2.01-2.35 eV, increased with increasing temperature. Consistently, the absorption edge shifts to lower energy values. The fundamental absorption edge corresponds to an indirect allowed transitions energy gap (2.08 eV at 300 K) that exhibits a temperature coefficient of -95 x 10(-4) eVK(-1).
Citation - WoS: 5
Citation - Scopus: 5
Growth and Temperature Tuned Band Gap Characteristics of Nabi(moo₄)_{2< Single Crystal}
(Iop Publishing Ltd, 2023) Isik, M.; Guler, I; Gasanly, N. M.
Structural and optical properties of double sodium-bismuth molybdate NaBi(MoO4)(2) semiconductor compound was investigated by x-ray diffraction, Raman and transmission experiments. From the x-ray diffraction experiments, the crystal that has tetragonal structure was obtained. Vibrational modes of the crystal were found from the Raman experiments. Transmission experiments were performed in the temperature range of 10-300 K. Derivative spectroscopy analysis and absorption spectrum analysis were performed to get information about the change in band gap energy of the crystal with temperature. It was observed that the band gap energies of the crystal at different temperatures obtained from these techniques are well consisted with each other. By the help of absorption spectrum which was obtained from transmission measurements performed at varying temperatures, absolute zero value of the band gap and average phonon energy as 3.03 +/- 0.02 eV and Eph = 24 +/- 0.2 meV, respectively. Moreover, based on absorption spectrum analysis the Urbach energy of the crystal was obtained as 0.10 eV.
Citation - WoS: 7
Citation - Scopus: 7
Phase-dependent characteristics of a superconducting junction by using the Schrodinger wave function
(Iop Publishing Ltd, 2007) Canturk, M.; Kurt, E.
As a macroscopic quantum system, superconducting junction devices are considered both analytically and numerically with the help of the Schrodinger wave equation. Considering the Cooper pair wave function psi in a time-dependent nature, the Hamiltonian of the system is constructed. The phase difference theta is assumed to be a unique independent variable of the superconducting junction in order to evaluate the characteristics of the system. The probability rho(theta) and super current j(theta) densities are determined for different applied voltages V. It is observed that both the amplitude and the period of the wave function psi(theta) have indicated different behaviors as functions of theta for various cases of V. Similarly, rho and j reflect drastic changes. It is shown that numerical results are in good agreement with the analytic results. Our results indicate consistency with some earlier experimental studies for different superconducting devices.
Citation - WoS: 4
Citation - Scopus: 7
An Extended Kalman Filtering Approach for the Estimation of Human Head Tissue Conductivities by Using Eeg Data: a Simulation Study
(Iop Publishing Ltd, 2012) Sengul, G.; Baysal, U.
In this study, we propose an extended Kalman filter approach for the estimation of the human head tissue conductivities in vivo by using electroencephalogram (EEG) data. Since the relationship between the surface potentials and conductivity distribution is nonlinear, the proposed algorithm first linearizes the system and applies extended Kalman filtering. By using a three-compartment realistic head model obtained from the magnetic resonance images of a real subject, a known dipole assumption and 32 electrode positions, the performance of the proposed method is tested in simulation studies and it is shown that the proposed algorithm estimates the tissue conductivities with less than 1% error in noiseless measurements and less than 5% error when the signal-to-noise ratio is 40 dB or higher. We conclude that the proposed extended Kalman filter approach successfully estimates the tissue conductivities in vivo.
Citation - WoS: 12
Citation - Scopus: 13
Fcnc Transitions of Λ_{b,c< To Nucleon in Sm}
(Iop Publishing Ltd, 2010) Azizi, K.; Bayar, M.; Sarac, Y.; Sundu, H.
We provide a comprehensive study of semileptonic flavor-changing neutral current transitions for Lambda(b) -> nl(+) l(-) and Lambda(c) -> pl(+) l(-) in the context of light cone QCD sum rules. Using the most general form of the interpolating current for Lambda(b),(c), as well as nucleon distribution amplitudes, we calculate all 12 form factors entering the calculations in full theory. We obtain the order of heavy quark effective theory violation and argue that the Lambda(b) -> nl(+) l(-) case can be studied at LHC, but the other one has a very small branching ratio.
Citation - WoS: 8
Citation - Scopus: 8
Study of the Structural and Optical Properties of Thallium Gallium Disulfide (tlgas₂) Thin Films Grown Via Thermal Evaporation
(Iop Publishing Ltd, 2022) Isik, M.; Karatay, A.; Ech-Chergui, A. N.; Gasanly, N. M.
Thallium gallium disulfide (TlGaS2) belonging to layered structured semiconducting family has been a significant compound due to its outstanding characteristics. Its layered characteristics take attention for two-dimensional (2D) material research area and thus TlGaS2 is known as promising layered compound to develop 2D materials for optoelectronic devices. To the best of our knowledge, the present work is the first one investigating TlGaS2 thin films grown by thermal evaporation method. The current study focused into the structural, morphological, and optical characteristics of thermally evaporated TlGaS2 thin films. X-ray diffraction pattern of the films exhibited one peak around 36.10 degrees which was associated with (-422) plane of the monoclinic crystalline structure. The atomic compositional ratio of Tl:Ga:S was found to be suitable for the chemical formula of TlGaS2. Scanning electron microscopy images showed uniformly and narrowly deposited nanoparticles with sizes varying between 100 and 200 nm. Room temperature transmission measurements were recorded to obtain the bandgap energy of the evaporated thin films. Tauc analyses indicated direct band gap energy of 2.60 eV. Finally, Urbach energy was obtained as 95 meV. The results of the present paper would provide valuable insight to 2D material technology to understand the potential device applications of the TlGaS2.
Citation - WoS: 9
Citation - Scopus: 11
Effect of Lithium Doping on the Properties of Tl-Based Superconductors
(Iop Publishing Ltd, 2001) Kayed, TS; Özkan, H; Gasanly, NM
The effects of lithium doping on the formation and properties of the T1-based superconductors have been studied. Lithium atoms up to around 3 mol.% have been added to the oxides of nominal composition Tl1.8Ba2Ca2.2Cu3Ox, and the usual solid-state reaction method has been applied. Lithium additions in the range 0.23-0.29 mol.% increase the fraction of the Tl-2223 phase and significantly improve the critical temperature of the samples. Higher amounts of lithium additions diminish the Tl-2223 phase, reduce the fraction of the Tl-2212 phase, and cause separate non-superconducting phases to be formed.

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