Browsing by Author "Surucu, Ozge"
Now showing 1 - 12 of 12
- Results Per Page
- Sort Options
Article Citation Count: 20Anisotropic mechanical properties of Tl4Ag18Te11 compound with low thermal conductivity(Academic Press inc Elsevier Science, 2020) Sürücü, Özge; Surucu, Ozge; Surucu, Gokhan; Deligoz, Engin; Electrical-Electronics EngineeringThe anisotropic mechanical properties of Tl4Ag18Te11 compound was investigated elaborately for the first time by using Density Functional Theory calculations with the Vienna Ab-initio Simulation Package in this work. Tl4Ag18Te11 compound was optimized in the I4mm space group and the formation energy was determined as a negative value that is the indication of the experimental synthesizability of this compound. The optimized crystal structure was employed for the calculations of the elastic constants and the obtained values revealed the mechanical stability of Tl4Ag18Te11 compound. The polycrystalline properties were determined such as shear modulus, Poisson's ratio, etc. In addition, the anisotropic elastic properties were presented. The direction dependent sound waves velocities, polarization of the sound waves, enhancement factor and the power flow angle were determined. The thermal conductivity studies were performed and the minimum thermal conductivity (0.259 W m(-1)K(-1)) and the diffusion thermal conductivity (0.202 W m(-1)K(-1)) were calculated. This study illustrates the capability of this compound for the thermoelectric materials.Article Citation Count: 4Complex nodal structure phonons formed by open and closed nodal lines in CoAsS and Na2CuP solids(Royal Soc Chemistry, 2022) Sürücü, Özge; Sun, Tingting; Surucu, Gokhan; Surucu, Ozge; Gencer, Aysenur; Wang, Xiaotian; Electrical-Electronics EngineeringTopological phononic states with nodal lines not only have updated our knowledge of the phases of matter in a fundamental way, but also have become a major frontier research direction in condensed matter physics. From a mathematical perspective, nodal line phonons can be divided into open and closed types. The present attempt is a report on the coexistence of such open and closed nodal line phonons in two realistic solids, CoAsS and Na2CuP, based on first-principles calculations. Furthermore, it is shown that the closed and the open nodal line states in CoAsS and Na2CuP have touching points and can form a complex nodal structure phonon in a momentum space. Due to the topologically non-trivial behavior of the complex nodal structure in both phonons, evident phononic surface states occur in the projected surfaces of both materials. In this way, these states, arising from the projected crossing points, can benefit experimental detection in follow-up studies. It has been stated that the open and closed nodal line states are formed by the crossings of two phonon branches and, hence, these two types of nodal line phonons are coupled with each other. The results obtained here could be considered as a breakthrough in clearly demonstrating the coexistence of the open and closed nodal line states in phonons and, for this reason, may inspire researchers seeking materials with such topological states in other bosons, such as photons.Article Citation Count: 3DFT Insights into Noble Gold-Based Compound Li5AuP2: Effect of Pressure on Physical Properties(Amer Chemical Soc, 2023) Sürücü, Özge; Gencer, Aysenur; Surucu, Ozge; Ali, Md. Ashraf; Electrical-Electronics EngineeringIn this study, the Li5AuP2 compound is investigated in detail due to the unique chemical properties of gold that are different from other metals. Pressure is applied to the compound from 0 to 25 GPa to reveal its structural, mechanical, electronic, and dynamical properties using density functional theory (DFT). Within this pressure range, the compound is optimized with a tetragonal crystal structure, making it mechanically and dynam-ically stable above 18 GPa and resulting in an increment of bulk, shear, and Young's moduli of Li5AuP2. Pressure application, furthermore, changes the brittle or ductile nature of the compound. The anisotropic elastic and sound wave velocities are visualized in three dimensions. The thermal properties of the Li5AuP2 compound are obtained, including enthalpy, free energy, entropy x T, heat capacity, and Debye temperature. The electronic properties of the Li5AuP2 compound are studied using the Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE) functionals. The pressure increment is found to result in higher band gap values. The Mulliken and bond overlap populations are also determined to reveal the chemical nature of this compound. The optical properties, such as dielectric functions, refractive index, and energy loss function of the Li5AuP2 compound, are established in detail. To our knowledge, this is the first attempt to study this compound in such detail, thus, making the results obtained here beneficial for future studies related to the chemistry of gold.Article Citation Count: 20Enhanced hydrogen storage of a functional material: Hf2CF2 MXene with Li decoration(Elsevier, 2021) Sürücü, Özge; Aydin, Sezgin; Surucu, Ozge; Wang, Xiaotian; Deligoz, Engin; Surucu, Gokhan; Electrical-Electronics EngineeringIn this paper, the hydrogen storage properties of the Li-decorated stable Hf2CF2 MXene layer, obtained by the exfoliation of Al from Hf2AlC and F-termination, are considered by using first-principles calculations based on Density Functional Theory. First, the stability characteristics of the host structure (Hf2CF2 layer) are examined by investigating bulk Hf2AlC. To enhance the adsorbed number of H-2 molecules, the well-defined initial H-2 coordinates are constructed by CLICH (Cap-Like Initial Conditions for Hydrogens) and Monte Carlo-based algorithms. After the geometry optimizations of the designed H-2 systems on the Li/Hf2CF2 layer, the adsorption energies of nH(2)/Li/Hf2CF2 n = 1-10, 15, 20 and 25 systems are calculated, and the suitable values (0.2-0.6 eV/H-2) are obtained up to 15H(2). For n = 20 and 25 systems, which have adsorption energies of 0.15 eV/H-2 and 0.16 eV/H-2, respectively. The structural properties and adsorption geometries of these molecules are analyzed. Additionally, the partial density of the states, electron density difference maps, and Mulliken atomic charges are presented to identify the actual binding mechanism of the systems. The results reveal that the Li-decorated Hf2CF2 MXene layer can be preferred for the hydrogen storage applications due to its stable nature and the convenient adsorption characteristics.Article Citation Count: 0Establishing the NiMo6Se8 Chevrel Phase as a Promising Material Using DFT(Wiley-v C H verlag Gmbh, 2024) Sürücü, Özge; Surucu, Ozge; Usanmaz, Demet; Oezel, Faruk; Gencer, Aysenur; Electrical-Electronics EngineeringIn this study, the NiMo6Se8 Chevrel phase is analyzed using Density Functional Theory (DFT) and the Vienna Ab-initio Simulation Package (VASP). The analysis focuses on the phase's structural, electrical, and mechanical characteristics to fill gaps in the current literature. The presence of a rhombohedral crystal structure confirms its thermodynamic stability, as indicated by a negative formation enthalpy, which suggests that it can be synthesized under favorable conditions. The electronic properties of the phase are analyzed, indicating that it exhibits semiconductor characteristics with a bandgap of 1.07 eV. This makes it appropriate for various technological applications. The estimated elastic constants provide an indication of mechanical strength and flexibility, with a noticeable presence of anisotropic elasticity. The confirmation of dynamical stability is achieved by analyzing the phonon dispersion curve, which reveals the absence of any negative frequencies. Furthermore, the material has a low thermal conductivity, increasing its suitability for thermoelectric applications. The analysis emphasizes the versatile capabilities of the NiMo6Se8 Chevrel phase, especially in thermoelectric and energy storage applications, showcasing its promising potential for future technological implementation.Article Citation Count: 28Illumination and voltage effects on the forward and reverse bias current-voltage (I-V) characteristics in In/In2S3/p-Si photodiodes(Springer, 2021) Sürücü, Özge; Surucu, Ozge; Terlemezoglu, Makbule; Parlak, Mehmet; Altindal, Semsettin; Electrical-Electronics EngineeringThe illumination and voltage effects on the I-V measurements of the fabricated In/In2S3/p-Si photodiode were investigated in dark and under various illumination intensities (20-100 mW/cm(2)) between +/- 2 V. Two linear regions in the forward-bias ln(I)-V plots were observed. The value of diode ideality factor (n) had an increasing trend with increasing illumination intensity while the barrier height (phi(Bo)) had a decreasing trend due to the increase of photocurrent. The photodiode properties were also investigated, and the value of linear-dynamic value range (LDR) was found to be 20.56 dB. The photoresponse (I-ph/I-dark), the photoresponsivity (R), and specific detectivity (D*) of the photodiode were calculated as a function of the illumination. The open-circuit voltage (V-oc) and short-current (I-sc) were found to be 0.36 V and 2.87 mA under 100 mW.cm(-2) illumination intensity, respectively. The possible conduction mechanisms (CMs) were investigated using the forward ln(I)-V and reverse ln(I)-V-0.5 plots. The energy-dependent surface states (N-ss) profile was extracted from the positive I-V data by considering voltage-dependent barrier height (BH) and ideality factor (n) in dark and illumination at 100 mW/cm(2).Article Citation Count: 17The investigation of electronic, anisotropic elastic and lattice dynamical properties of MAB phase nanolaminated ternary borides: M 2 AlB 2 ( M = Mn , Fe and Co ) under spin effects(Elsevier Science Sa, 2020) Sürücü, Özge; Yildiz, Bugra; Erkisi, Aytac; Wang, Xiaotian; Surucu, Ozge; Electrical-Electronics Engineering[No Abstract Available]Article Citation Count: 1Investigation of Tungsten-Based Seleno-Chevrel Compounds with Different Compositions for Efficient Water Splitting(Wiley-v C H verlag Gmbh, 2023) Sürücü, Özge; Surucu, Gokhan; Gencer, Aysenur; Surucu, Ozge; Ozel, Faruk; Ciftci, Yasemin; Electrical-Electronics EngineeringThis study investigates the photocatalytic water splitting performance for NixW6Se8(x=1,2,3,4)${\mathrm{N}}{{\mathrm{i}}_{\mathrm{x}}}{{\mathrm{W}}_6}{\mathrm{S}}{{\mathrm{e}}_8}\;( {x = 1, 2, 3, 4} )$ Chevrel phases with the chemical formula M(x)Mo(6)Ch(8), where M is a metal and Ch is a chalcogen, with x being 0, 1, 2, 3, or 4. Density Functional Theory (DFT) is used to study the NixW6Se8(x=1,2,3,4)${\mathrm{N}}{{\mathrm{i}}_{\mathrm{x}}}{{\mathrm{W}}_6}{\mathrm{S}}{{\mathrm{e}}_8}{\mathrm{\;}}( {x = 1, 2, 3, 4} )$ Chevrel phases, which includes earth-abundant elements for this specific study as an essential consideration for photocatalytic water splitting. The electronic properties are calculated for the NiW6Se8 and Ni2W6Se8 compounds with thermodynamical, mechanical, and dynamic stabilities. For photocatalytic water splitting, the band gaps below 1.23 eV are excluded, and the conduction and valence band levels are determined to examine the reduction and oxidation potentials for efficient photocatalytic water-splitting materials. An examination of the selected band gaps, along with the conduction and valence band levels, reveals that NiW6Se8 is suitable for both reduction and oxidation reactions; whereas, Ni2W6Se8 is a convenient material only for the reduction reaction. This is the first attempt, as far as the literature reveals, to study Chevrel phases in detail and to identify a suitable compound for photocatalytic water splitting.Article Citation Count: 37Lattice dynamical and thermo-elastic properties of M2AlB (M = V, Nb, Ta) MAX phase borides(Elsevier Science Sa, 2020) Sürücü, Özge; Gencer, Aysenur; Wang, Xiaotian; Surucu, Ozge; Electrical-Electronics EngineeringThe structural, electronic, dynamic, and thermo-elastic properties of M2AlB (X = V, Nb, Ta) MAX phase borides were investigated using first principle calculations as implemented in the Vienna Ab-initio Simulation Package (VASP) with the generalized gradient approximation (GGA). The obtained structural properties and formation energies showed the thermodynamic stability and synthesizability of M2AlB. The electronic band structures were determined and they revealed that these compounds had a metallic character. The dynamic stability of M2AlB compounds were investigated with phonon dispersion curves and these compounds were found to be dynamically stable. The elastic constants were also calculated to determine the mechanical stability and to obtain the polycrystalline properties such as bulk modulus, shear modulus, etc. The thermo-elastic properties (thermal expansion coefficient, heat capacity, entropy, and free energy) were studied in a temperature range in between 0 and 1000 K and a pressure range in between 0 and 30 GPa. In addition, the direction dependent sound wave velocities were studied in three dimensions. Moreover, the minimum thermal conductivities and the diffusion thermal conductivities of these compounds were determined. This work is the processor study for the investigation of the main physical properties of M2AlB (M = V, Nb, Ta) ceramic compounds to date. (C) 2019 Elsevier B.V. All rights reserved.Article Citation Count: 0Performance analysis of CuSbSe2 thin-film solar cells with Cd-free window layers(Elsevier, 2024) Sürücü, Özge; Bal, Ersin; Gencer, Aysenur; Parlak, Mehmet; Surucu, Ozge; Electrical-Electronics EngineeringThis study investigates novel thin-film solar cells featuring CuSbSe2 (CASe) with ZnSnO and ZnMgO windows in the layer superstrate structure. For glass/ITO/ZnMgO/CASe/Cu + Au, the J-V measurements reveal a shortcircuit current density (Jsc) of 19.4 mA/cm2, an open-circuit voltage (Voc) of 0.28 Volts, a fill factor (FF) of 39.14 %, and a power conversion efficiency (eta) of 2.13 %. Similarly, glass/ITO/ZnSnO/CASe/Cu + Au exhibits Jsc around 19.6 mA/cm2, Voc around 0.31 Volts, FF around 40 %, and eta of 2.43 %. This paper is a pioneering contribution, introducing novel thin-film solar cells with a distinctive superstrate structure utilizing CASe in conjunction with ZnSnO and ZnMgO windows. The comprehensive study presents the first-ever characterization and performance evaluation of these innovative configurations, shedding light on their unique potential in advancing sustainable solar energy technology.Article Citation Count: 1Physical characterization of thermally evaporated Sn-Sb-Se thin films for solar cell applications(Springer Heidelberg, 2023) Sürücü, Özge; Surucu, Ozge; Terlemezoglu, Makbule; Parlak, Mehmet; Electrical-Electronics EngineeringThe substitution of Sb in binary SnSe structure may lead to tailoring the physical properties of both SnSe and SbSe, promising absorber layers for thin film solar cells. The resulting Sn-Sb-Se structure could be an outstanding material for photovoltaic applications. In this study, Sn-Sb-Se thin films were deposited by thermal evaporation, and the effect of annealing on the films' structural, optical, and electrical properties were reported. XRD measurement shows that annealing at 300 degrees C yields the best crystalline quality, and structural parameters were calculated using XRD data. SEM and AFM measurements indicate deformation in the film surface after annealing at 400 degrees C. UV-Vis spectroscopy measurement provides a high absorption coefficient which indicates a direct band gap. The band gap and activation energies of the as-grown sample were found as 1.59 eV and 106.1 meV, respectively. The results of SEM, AFM, XRD, Raman, UV-Vis spectroscopy and temperature-dependent photoconductivity measurements were discussed throughout the paper.Article Citation Count: 3A study on the dark and illuminated operation of Al/Si3N4/p-Si Schottky photodiodes: optoelectronic insights(Springer Heidelberg, 2024) Sürücü, Özge; Yildiz, Dilber Esra; Yildirim, Murat; Electrical-Electronics EngineeringThis work extensively investigates the operation of an Al/ Si3N4/p-Si Schottky-type photodiode under dark and varying illumination intensities. The photodiode is fabricated by employing the metal-organic chemical vapor deposition (MOCVD) method. A thorough electrical characterization is performed at room temperature, encompassing measurements of current-voltage (I-V), current-time (I-t), capacitance-time (C-t), and conductance time (G-t). The photodiode's rectification factor and reverse bias area increased under illumination. The relationship between light power density, barrier height, and diode ideality factor is found. The study also found a strong correlation between light intensity and applied voltage on series resistance (R-s) and shunt resistance (R-sh). R-s values are calculated using Cheung's functions, revealing the diode's resistance behavior. The study also examines the photodiode's photoconductivity and photoconductance, finding a non-linear relationship between photocurrent and illumination intensity, suggesting bimolecular recombination. Calculated photosensitivity (K), responsivity (R), and detectivity (D*) values show the device's light response effectiveness, but efficiency decreases at higher illumination intensities. Transient experiments indicate stable and reproducible photocurrent characteristics, revealing photogenerated charge temporal evolution. This study provides a complete understanding of the Al/Si3N4/p-Si Schottky photodiode's behavior under different illumination intensities. The findings advance optoelectronic device knowledge and enable their use in advanced technologies.