Browsing by Author "Parlak, Mehmet"

Now showing 1 - 8 of 8

Citation - WoS: 1
Citation - Scopus: 1
Exploring the Thermal Stability of Sb2se3 for Potential Applications Through Advanced Thermal Analysis Methods
(Amer Chemical Soc, 2025) Altuntas, Gozde; Isik, Mehmet; Surucu, Gokhan; Parlak, Mehmet; Surucu, Ozge; Department of Electrical & Electronics Engineering; Electrical-Electronics Engineering; 15. Graduate School of Natural and Applied Sciences; 06. School Of Engineering; 01. Atılım University
Antimony selenide (Sb2Se3) is a promising material for energy applications, including photovoltaics, thermoelectrics, and photodetectors, due to its favorable electronic properties, availability, and low toxicity. However, its thermal stability, crucial for device efficiency and reliability, has been less explored, leaving a gap in understanding its high-temperature suitability. This study evaluates the thermal stability of Sb2Se3 using thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The results show that Sb2Se3 remains stable up to 500 degrees C, with two significant weight loss stages: 1.75% between 500 and 610 degrees C, and 3.50% between 610 and 775 degrees C, indicating decomposition processes. Activation energies for the decomposition phases were determined as 121.8 and 57.2 kJ/mol using the Coats-Redfern method. Additionally, an endothermic phase transition was observed between 599 and 630.6 degrees C via DSC analysis. These findings demonstrate Sb2Se3's potential for high-temperature energy applications, providing essential insights for optimizing its use in solar cells, thermoelectric devices, and other technologies.
Citation - WoS: 35
Citation - Scopus: 36
Illumination and Voltage Effects on the Forward and Reverse Bias Current-Voltage (i-V) Characteristics in In/In_{2< Photodiodes}
(Springer, 2021) Yukselturk, Esra; Surucu, Ozge; Terlemezoglu, Makbule; Parlak, Mehmet; Altindal, Semsettin; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
The 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).
Citation - WoS: 1
Integrating Theoretical and Experimental Approaches To Unveil the Mechanical Properties of Cusbse₂ Thin Films
(Iop Publishing Ltd, 2024) Surucu, Ozge; Gencer, Aysenur; Usanmaz, Demet; Parlak, Mehmet; Surucu, Gokhan; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
An exhaustive investigation of the mechanical characteristics of CuSbSe2 thin films is conducted in this study by combining experimental nanoindentation methods with theoretical simulations. The Ab-initio Molecular Dynamics (AIMD) calculations are performed with the machine learning (ML) force fields. By employing the Vienna Ab-initio Simulation Package (VASP) based on Density Functional Theory (DFT), theoretical inquiries are carried out to identify crucial parameters, such as bonding characteristics, elastic constants, hardness, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio. Experimental validation is conducted using nanoindentation to investigate load-dependent hardness and Young's modulus in a manner that closely matches the theorized predictions. The anomalies between experimental and theoretical outcomes are ascribed to anisotropic behavior and grain boundaries. Furthermore, an investigation is conducted into the directional dependence of sound wave velocities in the CuSbSe2 films, leading to the revelation of intricate elastic property details. By employing an integrated theoretical-experimental approach, the present attempt not only increases the knowledge concerning CuSbSe2 films but also fortifies the relationship between theory and experiment, thereby bolstering the dependability of our results. The insights provided as a result of this paper facilitate the development of CuSbSe2 film applications in a variety of technological fields in the future.
Citation - Scopus: 1
Nanowire Geometry Effects on Devices and Transport Mechanisms: Sns₂ Heterojunction
(Springer, 2023) Coskun, Emre; Emir, Cansu; Terlemezoglu, Makbule; Parlak, Mehmet; 01. Atılım University
The semiconductor nanowire technology has become essential in developing more complex and efficient devices. In this study, the Si nanowire (SiNW) heterojunction structure with a two-dimensional SnS2 thin film was investigated. The SiNW array was created by the metal-assisted etching method because of length control and production over large areas of nanowires. The created SiNW has more diminishing reflectivity compared with Si planar substrate. The diode characteristics of SnS2/SiNW and SnS2/Si planar heterojunctions were investigated by dark current analysis at room temperature, and the improving diode characteristics by the three-dimensional interface between SiNW and SnS2 thin film were discussed. Transport mechanisms of the SiNW heterojunction were also studied for various methods. Thermionic emission and thermally assisted tunneling models are the dominant mechanisms for low voltages (0.02-0.20 V), and the space charge limiting current mechanism dominates the current for comparingly high voltages (0.20-0.40 V). All the values reveal the significant impact of the SiNW on heterojunctions for improving efficiency.
A New Method To Determine the Continuous Refractive Index of an Absorbing Film by Generalized Stockwell Transform
(Elsevier Sci Ltd, 2023) Coskun, Emre; Emir, Cansu; Selamet, Semanur; Parlak, Mehmet; Ozder, Serhat; 01. Atılım University
Generalized Stockwell Transform (GST) was adapted to analyze a transmittance signal to continuously determine the refractive index and extinction coefficient. The process is built by analyzing oscillation frequencies of the transmission signal where oscillations exist. The simulation studies clearly show the advantage of the locally referenced phase property of the presented method. The validity of the method was checked for a CdS thin film. The results determined by the GST method are consistent with the results determined by envelope and other signal analyzing methods, and the literature. The noise and relative error analysis of the method was also discussed.
Citation - WoS: 4
Citation - Scopus: 4
Performance Analysis of Cusbse2 Thin-Film Solar Cells With Cd-Free Window Layers
(Elsevier, 2024) Surucu, Gokhan; Bal, Ersin; Gencer, Aysenur; Parlak, Mehmet; Surucu, Ozge; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
This 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.
Citation - WoS: 4
Citation - Scopus: 4
Physical Characterization of Thermally Evaporated Sn-Sb Thin Films for Solar Cell Applications
(Springer Heidelberg, 2023) Bektas, Tunc; Surucu, Ozge; Terlemezoglu, Makbule; Parlak, Mehmet; Electrical-Electronics Engineering; 06. School Of Engineering; 01. Atılım University
The 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.
Citation - WoS: 22
Citation - Scopus: 22
Structural, Morphological and Temperature-Tuned Bandgap Characteristics of Cus Nano-Flake Thin Films
(Elsevier, 2022) Isik, Mehmet; Terlemezoglu, Makbule; Gasanly, Nizami; Parlak, Mehmet; Department of Electrical & Electronics Engineering; 15. Graduate School of Natural and Applied Sciences; 01. Atılım University
Copper sulfide (CuS) thin films were produced by radio-frequency (RF) magnetron sputtering method. Structural, morphological and optical characteristics of deposited CuS films were presented. X-ray diffraction pattern showed two intensive peaks associated with hexagonal crystalline structure. Scanning electron microscopy image indicated that CuS films have nano-flake structured. Raman spectrum was reported to show vibrational characteristics of the CuS nano-flake thin films. Two peaks associated with Cu-S and S-S vibrations were observed in the Raman spectrum. Transmission spectra were recorded at various temperatures between 10 and 300 K. The analyses accomplished considering Tauc expression demonstrated that direct bandgap energy decreases from 2.36 eV (at 10 K) to 2.22 eV (at 300 K). Temperature-bandgap dependency was analyzed considering Varshni and Bose-Einstein expressions to reveal bandgap at 0 K, rate of change of bandgap and Debye temperature. CuS nanoflake thin film may be used in optoelectronic and photocatalysis applications thanks to its direct and narrow bandgap energy characteristics.