Yazar "Kilic, Hamdi Sukur" seçeneğine göre listele

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    Determination of photovoltaic parameters of CIGS hetero junction solar cells produced by PLD technique, using SCAPS simulation program
    (Pergamon-Elsevier Science Ltd, 2021) Gezgin, Serap Yigit; Houimi, Amina; Gundogdu, Yasemin; Mercimek, Bedrettin; Kilic, Hamdi Sukur
    In this study, CIGS ultrathin films of 52 nm, 89 nm, 183 nm and 244 nm thicknesses were grown on a n-Si substrate using PLD technique, then Ag/CIGS/Si/Al hetero-junction solar cells were formed by producing front finger and back contact. While the thickness of CIGS ultrathin film is increased, their grain sizes are also increased, crystal structures are developed and more light is absorbed within the thin film. The straight characteristics of hetero-junctions have been improved while the thicknesses of CIGS ultrathin film is decreased according to J-V characteristics of the hetero-junctions in the darkness. In addition, depending on CIGS ultrathin film thickness, the photovoltaic behavior of CIGS/Si hetero junction solar cells has been studied and interpreted in detail in this article. It can be concluded that CIGS/Si hetero-junction solar cell device produced based on CIGS ultrathin film of 183 nm thickness shows the highest short circuit current density and power conversion efficiency values among other thicknesses, with respect to J-V curve under the illumination (AM 1.5 solar radiation in 80 mW/cm2). Using SCAPS 1-D program, we have been able to successfully simulate CIGS/Si hetero-junction of 183 nm thickness.
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    DFT Study of Conformational Analysis, Molecular Structure and Properties of para-, meta- and ortho 4-Methoxyphenyl Piperazine Isomers
    (Springer, 2021) Ekincioglu, Yavuz; Kilic, Hamdi Sukur; Dereli, Omer
    In this study, conformer analysis of isomer structures of para-, meta- and ortho 4-methoxyphenyl piperazine molecules was performed using the Spartan 08 package program. The optimized geometrical parameters, energies for the highest occupied molecular orbital and the lowest unoccupied molecular orbitals, chemical reactivity descriptors, nonlinear optical properties, Mulliken population analysis, molecular electrostatic potential map, thermodynamic properties and UV-Vis spectral analysis of isomers of the N-(4-methoxyphenyl) piperazine molecule were predicted using the density functional theory (DFT) and TD-DFT/B3LYP/6-311++G(d,p) methods. The theoretical results obtained were compared with experimental results available in the literature so far, and these results were discussed for each isomer.
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    A DFT/TD-DFT Study on the Molecular Structure Absorption and Fluorescence Spectra of Gas/Solution Phases Adenosine 5?-triphosphate Molecule
    (Gazi Univ, 2022) Ekincioglu, Yavuz; Kilic, Hamdi Sukur; Derel, Omer
    In this study, the conformational structure of the tetra-protonated Adenosine 5'triphosphate molecule has been investigated using Spartan 08 package program with the molecular dynamics method. Following the conformational analysis; geometry optimization, excited states, absorption and fluorescence (emission) spectra, molecular orbitals, chemical hardness, electronic chemical potential, electronegativity and electrophilicity indexes of the molecule were calculated by using density functional theory and time-dependent density functional theory method with B3LYP functional with 6-311+G (d, p) basis set. All calculations for the tetra-protonated ATP molecule have also been carried out both in the gas phase and in the aqueous solution and then results were compared with the experimental data reported in the literature.
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    The Effect of CZTS Ultrathin Film Thickness on the Electrical Characteristic of CZTS/Si Heterojunction Solar Cells in the Darkness and under the Illumination Conditions
    (Springer, 2021) Gezgin, Serap Yigit; Houimi, Amina; Mercimek, Bedrettin; Kilic, Hamdi Sukur
    In this study, Ag/CZTS/Si/Al heterojunction solar cells were produced depending on some parameters of CZTS ultrathin active film layers grown on a n-Si wafer by PLD technique. CZTS ultrathin films have been produced as a function of the number of laser pulses and then annealed in a tube oven as a function of sulfurization temperature. The crystal structure, the optical and morphological properties of grown&annealed CZTS ultrathin films were examined by XRD, UV-vis spectra, AFM, respectively. The electrical characteristics of CZTS heterojunction solar cell in the darkness, which were investigated by the conventional J-V Method, Cheung Cheung Method and Norde Method. As the thickness of CZTS ultrathin films increased, the forward current of CZTS heterojunctions increased and their ideality factor, serial resistance and barrier height decreased. Also, the efficiency of Ag/CZTS/Si/Al heterojunction solar cells have been examined and characterised as a function of CZTS ultrathin film thickness under the illumination conditions. J-V curves of CZTS heterojunction solar cells were determined under AM 1.5 solar radiation in 80 MW/cm(2), all CZTS heterojunction solar cells have exhibited the photovoltaic behaviour. J(sc), V-oc, FF, eta parameters of Ag/CZTS/Si/Al heterojunction solar cells were measured, interpreted and compared with each other.
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    Effect of Li Doping on Cu2SnS3/n-Si Heterojunction Solar Cells: Experiments and Simulation
    (Wiley-V C H Verlag Gmbh, 2023) Houimi, Amina; Gezgin, Serap Yigit; Mercimek, Bedrettin; Kilic, Hamdi Sukur
    Cu2SnS3 (CTS) semiconductor material owns very interesting absorbing properties that allow it to be effectively utilized in many thin-film-based heterojunction solar cells. In this work, using the ball milling method, a mixture of pure elemental powders is used to synthesize CTS material. Homemade undoped and Li-doped target pellets are used to form CTS-doped and CTS-undoped thin films. The crystallinity investigation of synthesized targets and thin films confirms the formation of CTS tetragonal phase. Compositional, morphologic, and optic studies are also made to examine the effect of Li atom incorporation on different properties of CTS thin films. These CTS thin films are also incorporated into heterojunction solar cells (Al/n-Si/CTS/Ag and Al/n-Si/Li0.03CTS/Ag). In addition, J-V characteristics of both CTS and Li0.03CTS solar cells are demonstrated and discussed in details. The effect of CTS thin films' thickness on the performance is studied using Solar Cell Capacitance Simulator (SCAPS-1D) program. The results of the calculation are discussed in details and compared with the experimental results. An increase in efficiency is achieved in solar cells based on Li-doped CTS thin films, and it is discussed in detail along with SCAPS-1D simulation that is carried out depending on the thickness of CTS thin films.
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    Molecular Structure and TD-DFT Study of the Xylene Isomers
    (Gazi Univ, 2019) Kepceoglu, Abdullah; Gundogdu, Yasemin; Dereli, Omer; Kilic, Hamdi Sukur
    In this work, we have investigated the xylene isomers in concepts of vertical and adiabatic ionization energy parameters and molecular orbital (HOMO-1, HOMO/SOMO, LUMO, LUMO+1) energies of the neutrals and singly charged cation radicals. As a first step of the calculations, conformational analysis has been performed for all isomers using the semi-empirical method with PM3 core type Hamiltonian. Geometry optimization and frequency calculations were performed by using Density Functional Theory (DFT) with Becke, three-parameter, Lee-Yang-Parr (B3LYP) exchange-correlation functional and 6-311++G(d,p) basis sets. UV-Vis electronic spectra of the neutral xylene isomers were calculated by using the TD-DFT method with cam-B3LYP functional and 6-311++G(2d,2p) basis set.
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    Numerical analysis of CZTS/n-Si solar cells using SCAPS-1D. A comparative study between experimental and calculated outputs
    (Elsevier, 2021) Houimi, Amina; Gezgin, Serap Yigit; Mercimek, Bedrettin; Kilic, Hamdi Sukur
    CZTS (Cu2ZnSnS4) is a p-type semiconductor material which has been intensively used as an absorbing layer for thin film solar cells. Using pulsed laser ablation + deposition technique, we have been able to successfully form a CZTS/n-Si heterojunction solar cells with an optimum thickness of 210 nm of CZTS thin film. Different characteristics (optic, crystal and morphologic) of CZTS thin films have been investigated according to the thickness of CZTS thin film. We have accomplished a simulation work based on CZTS/c-Si hetero junction solar cells using SCAPS-1D. Into this model, experimental data including band gap, thickness and absorption coefficient have been introduced. The change of hole carrier's density in CZTS thin film, interface defect density in CZTS/n-Si hetero junction and device temperature have been found to be very influential on J-V characteristics of a CZTS (210 nm)/c-Si solar cell. SCAPS-1D model has also been introduced for the other three different CZTS thin films thicknesses and the results obtained from both SCAPS-1D program and experimental measurements have been found to be very close to each other.
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    Observation of negative photoresponse in joule-heated Au/Cu2SnS3 ternary chalcogenide thin film deposited by low energy pulsed laser deposition
    (Elsevier, 2022) Basyooni, Mohamed A.; Belaid, Walid; Houimi, Amina; Zaki, Shrouk E.; Eker, Yasin Ramazan; Gezgin, Serap Yigit; Kilic, Hamdi Sukur
    Gold (Au) nanoparticles trapped within Cu2SnS3 (CTS) thin films were effectively deposited on a low-cost glass substrate using a simple pulsed laser deposition of 15 mJ for 5 ns at a 10 Hz repetition rate. The film's structural, morphological, topography, optical, and optoelectronic properties were investigated. Highly crystalline ternary chalcogenide CTS with tetragonal symmetry and 17 nm grain size is prepared. The 110 0 resistivity of the thin film increases up to 125 0 indicating a negative photoresponse under visible light excitation. The decrease in the photocurrent is also observed with Cu2SnS3/Au/Cu2SnS3 sandwich ternary chalcogenide structure at resistivities values from 31 to 35 0 and a Joule effect influence the presence of plasmonic Au nanoparticle interlayers involved a lower phonon disorder given a higher photoresponse effect as predicted from Urbach energy.
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    Optical, Optoelectronic, and Third-Order Nonlinear Photonics of Ultrathin Molybdenum Oxide Film Deposited by Atomic Layer Deposition
    (Wiley-V C H Verlag Gmbh, 2023) Basyooni, Mohamed A. A.; Gundogdu, Yasemin; Kilic, Hamdi Sukur; Eker, Yasin Ramazan
    The atomic layer deposition (ALD) technique has attracted significant attention because it enables the control of film synthesis at the subnanometre scale. Herein, molybdenum oxide (MoO3) ultrathin films using the ALD system through Bis(t-butylimido)bis(dimethylamino)molybdenum (VI) as a molybdenum (Mo) source are prepared. To understand the effect of deposition temperature, thin films are prepared at three different temperatures 100, 150, and 250 degrees C. The morphological and elemental properties are assessed using a field emission scanning electron microscope, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy techniques. It is observed that the film thicknesses increase with the increase in the deposition temperature. It is found that the film growth at 150 degrees C is the most potential one for UV optoelectronic applications with high stability even under low applied bias voltages. Moreover, these films show interesting nonlinear optical behaviors as investigated with the z-scan technique applying open and closed aperture methods. The calculated nonlinear optical parameters including nonlinear absorption coefficient (beta), nonlinear refractive index (n(2)), nonlinear refractive coefficient (gamma), and third-order nonlinear susceptibility (chi((3))) are 10(-11) m W-1, 10(-16) cm(2) W-1, 10(-11) cm(2) W-1, and 10(-11) esu, respectively.
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    A theoretical study of the effects of electric field, hydrostatic pressure, and temperature on photoionization cross-section of a donor impurity in (Al, Ga)N/AlN double triangular quantum wells
    (Iop Publishing Ltd, 2023) Belaid, Walid; El Ghazi, Haddou; Zaki, Shrouk E.; Basyooni, Mohamed A.; Tihtih, Mohammed; Ennadir, Redouane; Kilic, Hamdi Sukur
    The aim of this research is to analyze the influence of various factors on the photo-ionization cross-section in (Al, Ga)N/AlN double triangular quantum wells. Using the finite difference method, the effects of the electric field, hydrostatic pressure, temperature, and Ga concentration were investigated within the effective mass and parabolic approximations. Our findings show that the photo-ionization cross-section (PICS) is highly dependent on all the variables under consideration. The optical spectra were blue-shifted with increasing electric field and pressure and red-shifted with increasing temperature and impurity displacement far from the center of the structure. Furthermore, it was found that changes in gallium content and impurity position can increase the PICS amplitude. A comparison of the obtained results with the existing literature as a limiting case of the reported problem is also provided, and excellent agreement is found.