Yazar "Sarica, Emrah" seçeneğine göre listele

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    Characterization of CdS films and CdS/Si heterojunctions prepared by ultrasonic spray pyrolysis and their response to light
    (Elsevier, 2020) Bilgin, Vildan; Sarica, Emrah; Demirselcuk, Barbaros; Erturk, Kadir
    In this work CdS thin films were deposited onto glass and p-Si substrates by ultrasonically spraying of precursor solutions prepared in molarity ranging from 0.025 M, to 0.1 M. Structural investigations revealed that all films have hexagonal structure and mean crystallite size was found to be in the range of 18 nm-21 nm. On the other hand, CdS films exhibited 65-70% optical transmittance and band gap energy for all films was found to be about 2.42 eV. Electrical measurements of CdS/Si heterojunctions were carried out under both dark and illumination conditions. Calculated ideality factor and zero-bias barrier height ranged from 3.02 to 2.66 and 0.74 eV-0.78 eV according to TE theory whereas they ranged from 6.91 to 4.73 and 0.71 eV-0.74 eV according to Cheungs' method. Increase in reverse saturation current when heterojunctions were illuminated indicated that they have good sensitivity to solar light.
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    Effect of Pb:S molar ratio in precursor solution on the properties of lead sulphide thin films by ultrasonic spray pyrolysis
    (Elsevier Sci Ltd, 2017) Sarica, Emrah; Bilgin, Vildan
    In this work, PbS thin films were deposited onto glass substrate at 225 degrees C by spraying precursor solution prepared with different molar ratio of lead acetate and thiourea as a source of Pb2+ and S2- respectively in order to investigate the effect of Pb:S molar ratio in the precursor solution on the physical properties of PbS thin films. Structural investigations carried out by X-ray diffractometer have shown that all films have fcc cubic structure and the average crystal size increased from 11 nm to 25 nm with the increasing the thiourea ratio in the precursor solution. In order to analyze the surface morphology of PbS thin films, AFM and SEM images were taken and elemental analysis of the films was performed by EDS. Optical transmittance and absorption spectra show that all deposited films have fairly low transmittance and high absorbance in the visible region. Additionally, it was determined that optical band gap of the deposited films were varied between 1.18 eV and 1.37 eV. As a consequence of electrical investigations, it was seen that all films have p-type conductivity and electrical resistivity decreased by increasing thiourea molar ratio in the precursor solution. All examinations have revealed that the molar ratio of lead acetate and thiourea has a significant effect on the physical properties of PbS thin films.
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    Fine-tuning SnO2 films: Unleashing their potential through deposition temperature optimization by ultrasonic spray pyrolysis
    (Elsevier Sci Ltd, 2024) Sarica, Emrah; Ozcan, Hakan Bilal; Gunes, Ibrahim; Terlemezoglu, Makbule; Akyuz, Idris
    In this study, the optimization of the deposition temperature, which directly affects the crystallinity, morphology, and electrical conductivity of SnO2 films deposited onto Corning Eagle XG glass substrates using the ultrasonic spray pyrolysis technique, was investigated to tailor their physical properties for various applications. Structural analyses revealed that the films had a tetragonal rutile structure, and while films deposited at lower temperatures exhibited a higher prevalence of (200) oriented planes, yet this decreased with an increase in deposition temperature. Morphological analyses showed that the films consisted of grains with octahedral shapes, and films deposited at lower temperatures were found to be more compact. The films had bandgap energy ranges between 3.96 eV and 4.02 eV. Hall effect measurements revealed that not only the carrier concentration decreased from 4.52 x 10(19) cm(-3) to 0.80 x 10(19) cm(-3), but the mobility also decreased from 23.32 cm(2)/Vs to 12.85 cm(2)/Vs. Among all the films, it was noted that the films deposited at 350 degrees C had the highest figure of merit which is 12.3 x 10(-4) Omega(-1). It can be concluded that the changes underlying these variations are associated with structural and morphological changes depending on the substrate temperature. Also, significant results have been attained in applications where precise control over crystal structure and surface morphology is crucial.
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    Flow rate-dependent properties of SnO2 thin films deposited by ultrasonic spray pyrolysis
    (Elsevier, 2024) Gunes, Ibrahim; Sarica, Emrah; Ozcan, Hakan Bilal; Terlemezoglu, Makbule; Akyuz, Idris
    This study unveils the outcomes of fabricating and characterizing SnO2 thin films through ultrasonic spray pyrolysis. Also, it focuses on the effect of manipulating flow rates on their structural, optical, and electrical characteristics. Structural analysis revealed that the films exhibited a tetragonal rutile structure and (200) crystallographic planes become preferential as the flow rate increases. Crystallite size and lattice strain were calculated using the Debye-Scherrer and Williamson-Hall methods, demonstrating that higher the flow rate resulted in larger crystallite sizes and reduced lattice strain. SEM images showed that all films have uniform and consistent film thickness and grain size enlarged with the solution flow rate as well. The films exhibited high optical transparency (>80%) in the visible spectrum, making them suitable for transparent conductive applications. The band gap of the films decreased gradually with flow rates, and the Urbach energy slightly increased. Hall effect measurements revealed higher flow rates resulted in lower sheet resistance (lowest is 1.32 x 10(2) Omega/sq) and higher carrier mobility (highest is 22.12 cm(2)/V.s), indicating improved electrical properties. These findings offer valuable perspectives for forthcoming researches.
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    Fluorine-doped tin oxide films via ultrasonic spray pyrolysis: Investigation of physical properties post-annealing and their potential for TCO applications
    (Elsevier, 2024) Gunes, Ibrahim; Sarica, Emrah; Bilgin, Vildan; Kucukarslan, Ayse; Ozder, Serhat
    In this study, undoped tin oxide (SnO2) and fluorine (F)-doped SnO2 (FTO) films at various doping levels were deposited on glass substrates using the ultrasonic spray pyrolysis technique, followed by an annealing process applied to the films after deposition. In line with this, the study reveals the significant impact of the fluorine doping level optimization on certain physical properties such as the structural, optical, and electrical characteristics of the obtained films, and presents the consequences of the variation in these physical properties for adaptability in various optoelectronic applications. No diffraction peaks were observed in the X-ray diffraction patterns of the deposited films. After the annealing process, however, films with a polycrystalline form and a rutile tetragonal crystal structure were obtained. It was observed that the crystallization levels were better in films doped with 5 % and 10 % F. The optical band gap values of the films were determined to vary between 3.35 eV and 3.68 eV. Furthermore, it was found that with the increase in F doping level, the resistivity (ranging from 2.1 Omega cm to 43.5 Omega cm) and sheet resistance (ranging from 1.62x10(5) Omega/sq to 35.9x10(5) Omega/sq) values of the films decreased, while the figure of merit values (ranging from 0.12x10(-8) Omega(-1) to 67.1x10(-8) Omega(-1)) increased. Among all FTO films, it was revealed that films doped with 10 % F exhibited the highest optical transmittance, the lowest electrical resistivity, and the highest figure of merit values.
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    Iron doped ZnO thin films deposited by ultrasonic spray pyrolysis: structural, morphological, optical, electrical and magnetic investigations
    (Springer, 2018) Bilgin, Vildan; Sarica, Emrah; Demirselcuk, Barbaros; Turkyilmaz, Seren
    In this work, undoped and Fe-doped ZnO thin films at various concentrations (2, 4 and 6 at.%) were deposited onto glass substrate by using ultrasonic spray pyrolysis in order to investigate the effect of Fe doping on the structural, morphological, optical, electrical and magnetic properties of ZnO thin films. X-ray diffractometer (XRD) results revealed that all deposited thin films have hexagonal wurtzite structure and Fe doping led to decrease in mean crystallite size. Atomic force microscopy images showed that thin films were composed of tightly packed grains. Optical examinations indicated that optical transmittance remarkably decreased with the increase in the amount of Fe concentration in thin films. Additionally, optical band gap of deposited films were determined in the range of 3.26-3.29 eV. It was determined that all deposited thin films have n-type conductivity and electrical resistivity increased up to 253.6 Omega cm as a consequence of Fe doping. Vibrating sample magnetometer measurements showed that all films have ferromagnetic behavior.
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    Nano-titanium coating on glass surface to improve platelet-rich fibrin (PRF) quality
    (Springer, 2024) Tunali, Mustafa; Ercan, Esra; Pat, Suat; Sarica, Emrah; Bagla, Aysel Guven; Ayturk, Nilufer; Siddikoglu, Duygu
    The quality of platelet-rich fibrin (PRF) is contingent on the surface characteristics interfacing with blood. Titanium's superior platelet activation, surpassing silica, has made Titanium-platelet-rich fibrin (T-PRF) a favored autogenous bone graft material due to its extended degradation time. Pioneering a novel approach, this study aims to achieve an enhanced fibrin structure using glass tubes coated with nano-titanium, marking the surface's debut in our PRF production endeavors. Employing a rapid thermionic vacuum arc (TVA) process under high vacuum, we conducted comprehensive analyses of the tubes. Comprehensive analyses, including X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), were conducted on the nano-titanium-coated glass tubes. Three PRF types were formulated: silica-activated leukocyte- and platelet-rich fibrin (L-PRF, control group), machined-surface titanium tubes (T-PRF), and nano-titanium-coated tubes (nanoT-PRF). Analyses unveiled denser fibrin areas in nanoT-PRF than T-PRF, with the least dense areas in L-PRF. Cell distribution paralled between nanoT-PRF and T-PRF groups, while L-PRF cells were embedded in the fibrin border. NanoT-PRF exhibited the densest autogenous fibrin structure, suggesting prolonged in vivo resorption. Additionally, we explore the potential practicality of single-use production for nanoT-PRF tubes, introducing a promising clinical advancement. This study marks a significant stride in innovative biomaterial design, contributing to the progress of regenerative medicine.
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    Non-stoichiometric effect and disorder in as-prepared Cu2ZnSnS4 films deposited at different temperatures by ultrasonic spray pyrolysis
    (Elsevier Sci Ltd, 2022) Gunes, Ibrahim; Bilgin, Vildan; Sarica, Emrah
    A better understanding of its crystal structure, the formation of possible secondary phases, defects and Cu-Zn disorder effects is needed to improve the photovoltaic device performance of CZTS films. In this direction, the effect of deposition temperature on the structural inhomogeneities, such as secondary phases and Cu-Zn dis-order, etc. as well as opto-electrical properties of CZTS were experimentally examined. For this purpose, a non-stoichiometric spraying solution was prepared and ultrasonically sprayed onto glass substrates at different deposition temperatures (350 degrees C, 400 degrees C, 450 degrees C, and 500 degrees C) to obtain CZTS films. Afterward, the structural, morphological, elemental, optical, and electrical properties of the deposited films were investigated in detail. By Lorentzian deconvolution of Raman spectra, 14 Raman vibrational modes were detected and seven of these were assigned to the secondary phases. Also, the ordered-kesterite phase (337 cm-1) of CZTS was found to crystallize along with the disordered-kesterite phase (329 cm-1) due to the disorder of the cation (Cu-Zn) sublattice. Optical band gaps for CZTS films decreased from 1.89 eV to 1.42 eV with increasing in deposition temperature. It was seen that not only optical band gaps but also Cu-Zn disorder and the amount of secondary phases in CZTS films tightly depend on the deposition temperature.
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    Sol-gel derived ZnO:Sn thin films and fabrication of n-ZnO:Sn/p-Si heterostructure
    (Elsevier, 2021) Sarica, Emrah; Gunes, Ibrahim; Akyuz, Idris; Bilgin, Vildan; Erturk, Kadir
    In this work ZnO:Sn thin films were deposited onto glass and p-Si substrates by spin coating of prepared sols which contains different amounts of Zn(CH3COO)(2)center dot 2H2O and SnCl2 (0, 5, 10 and 15%). Physical properties of ZnO films were examined as a function of SnCl2 in prepared sols. In addition to that, heterostructure examinations were also carried out by depositing all films on p-Si substrates as well. XRD studies revealed that all films have c-axis orientation with crystallite sizes between 38 and 47 nm. AFM and SEM images showed that morphology of the films remarkably deteriorated with the increase in amount of SnCl2 in sol. Optical transmittance and absorbance spectra showed that films have high transmittance and low absorbance in the visible region. Besides, optical band gap increased from 3.27 eV to 3.37 eV. Additional band gap energies were determined for 10% and 15% Sn doped ZnO films. Room temperature photoluminescence spectra for all films were deconvoluted for the evaluation of all emission bands and it was noted that incorporation of SnCl2 into sol led to enhancement of UV-blue emission bands and caused emission bands related to oxygen vacancies to diminish. Four-point-probe measurements revealed that electrical resistivity of ZnO:Sn films increased from 3.20 x 100 omega cm to 2.82 x 104 omega cm and diode ideality factor of Ag/ZnO:Sn/p-Si/Au heterostructure was calculated to be in the range of 2.14-4.59 while zero-bias barrier height is in the range of 0.63-0.78 eV.
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    Structural, optical, electrical and magnetic studies of ultrasonically sprayed ZnO thin films doped with vanadium
    (Elsevier Science Sa, 2016) Sarica, Emrah; Bilgin, Vildan
    Undoped and vanadium (V) doped (3, 6, 9 and 12 mol%) ZnO thin films were deposited onto glass substrates at the substrate temperature of 400 +/- 5 degrees C by ultrasonic spray pyrolysis technique. Depending on the doping concentration, the variation in the structural, morphological, elemental analysis, and optical, electrical and magnetic properties were investigated by means of X-ray diffractometer (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), UV-vis spectrophotometer, current-voltage (I-V) measurements and vibrating sample magnetometer (VSM), respectively. The X-ray diffraction studies have revealed that all the films were polycrystalline with hexagonal wurtzite crystal structure. The transmittance in the visible region varied between 55 and 75% and it was observed that transmittance of deposited films decreased after incorporation of vanadium. The electrical resistivity studies for all the films were carried out by using the two-probe method and it was seen that the electrical resistivity of the ZnO films decreased sharply as a consequence of V doping. The VSM measurements showed that all deposited films have intrinsic ferromagnetic behavior at room temperature and it was also found that the ferromagnetic behavior of all the films was obviously affected by doping with vanadium. (C) 2015 Elsevier B.V. All rights reserved.
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    Study of some physical properties of ultrasonically spray deposited silver doped lead sulphide thin films
    (Elsevier Sci Ltd, 2017) Sarica, Emrah; Bilgin, Vildan
    In this study, undoped and Ag doped PbS thin films at different concentrations were deposited onto glass substrates at 225 degrees C by using ultrasonic spray pyrolysis technique, in order to investigate the effect of Ag doping on the physical properties of PbS thin films. Structural investigations revealed that all doped PbS: Ag thin films have cubic structure and Ag doping enhances crystalline level of PbS thin films. It was determined that average crystallite size of PbS: Ag thin films increased from 24 nm to 49 nm by increasing Ag doping concentration. Morphological studies showed that surfaces of the films become denser after Ag doping. Optical transmittance and absorption spectra revealed that all deposited thin films have low transmission and high absorbance within the visible region and band gap energy of the PbS:Ag thin films were determined to be in the range of 1.37 eV and 1.28 eV by means of optical method. Electrical conductivity type of PbS: Ag films was determined to be p-type and calculated electrical resistivity was found to be lowest for Ag-doped PbS thin films at 2%.
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    The Effect of Fe and Co doping on the Physical Properties of CdO Films Deposited by Ultrasonic Spray Pyrolysis
    (Springer, 2025) Demirselcuk, Barbaros; Gunes, Ibrahim; Sarica, Emrah; Kus, Esra; Kucukarslan, Ayse; Bilgin, Vildan
    In this study, Cadmium Oxide (CdO) semiconductor films with different iron (Fe) and cobalt (Co) concentrations have been produced at 350 degrees C substrate temperature on the glass substrates by the ultrasonic spray pyrolysis method. In the first part of this study, the Fe element was doped in different ratios (2, 4, 6%) to CdO films, and the films were characterized. At the end of this stage, the optimum Fe doping ratio was determined for CdO films. In the second step, CdO films were dually doped with Fe + Co. The electrical resistivities of CdO:Fe films were determined using a four-probe technique to measure their conductivities, carrier concentrations, mobilities, and electrical conductivity types through Hall measurements. The produced films showed n-type electrical conductivity. It was determined that with increasing doping ratios, the electrical resistivity generally increased, and the films exhibited n-type conductivity. The XRD patterns revealed that the crystal structures of the films were polycrystalline and cubic in structure. The lections of (111), (200), (220), (311), and (222) planes were observed in the XRD patterns. Upon examination of the SEM images, it was observed that the films had nearly homogeneous surfaces and good adhesion to the substrate. By utilizing the fundamental absorption spectra of the films, it was determined that they exhibited direct bandgap transitions, and the bandgap energy values ranged from 2.34 to 2.65 eV. In the structural analysis, all films were found to have a polycrystalline structure and cubic CdO crystal system. When the SEM images of CdO:(Fe + Co) films were examined, it was observed that the films had almost homogeneous surfaces. Based on all these analyses, it was concluded that the doping elements Fe and Co significantly influenced the physical properties of CdO thin films.
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    Ultrasonically sprayed cobalt oxide thin films: Enhancing of some physical properties by nickel doping
    (Elsevier, 2021) Kus, Esra; Kucukarslan, Ayse; Demirselcuk, Barbaros; Sarica, Emrah; Akyuz, Idris; Bilgin, Vildan
    In this study, the effect of Ni doping (3, 6, 9 at%) on structural, optical, electrical and magnetic properties of Co3O4 films was reported. Films were grown at 300 +/- 5 degrees C substrate temperature via ultrasonic spray pyrolysis (USP) technique. The structural analyses showed that undoped and Ni (3%) doped films exhibit an amorphous structure. Ni doping at higher ratios caused the films to have improved crystallinity. Optical band gap values the films were found to be between 2.03 and 2.08 eV with an additional sub band corresponding to energies varying between 1.35 and 1.46 eV. The electrical conductivity values of the films increased significantly depending on the Ni doping. The hysteresis curves of the films showed that the films have weak ferromagnetic properties. Ni doping significantly improved the structural and electrical properties of Co3O4 films making them suitable materials for technological applications. (c) 2021 Elsevier B.V. All rights reserved.