Yazar "Güneş, İbrahim" seçeneğine göre listele
Listeleniyor 1 - 9 / 9
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Enhancing π-SnS thin films and fabrication of p-SnS/n-Si heterostructures through flow rate control in ultrasonic spray pyrolysis for improved photovoltaic performance(Springer Heidelberg, 2024) Güneş, İbrahimThis study presents findings related to the characterization of cubic SnS (pi-SnS) thin films and p-SnS/n-Si heterojunction structures produced simultaneously using the ultrasonic spray pyrolysis technique. In this context, the impact of different spray solution flow rates on the morphological, structural, optical, and electrical characteristics of the films was examined. Morphological analyses revealed that higher flow rates resulted in films with denser and smoother surfaces, approximately 6 nm in roughness. Additionally, it was observed that both the thickness and the growth rate of the films could be adjusted through the modulation of the flow rate. Structural analyses determined that the crystallite size increased and micro-strain values decreased with increasing flow rates. Optical evaluations indicated a decline in the optical band gap of the thin films from about 1.8 eV to 1.7 eV as the flow rates increased. This trend was consistently observed in the data obtained using the Tauc method and the derivative of transmission with respect to wavelength versus photon energy graphs. Electrical analyses revealed that the resistivity values of the thin films increased from 5.24 x 105 ohm cm to 1.64 x 106 ohm cm with increasing flow rates. Furthermore, I-V analyses of the Au/p-SnS/n-Si/Ag heterojunction structures indicated significant variability in key electrical properties. The saturation currents displayed a broad range, suggesting varying efficiencies in charge carrier collection across different samples. Similarly, the change of ideality factors pointed to differences in charge transport mechanisms, while the shifts in barrier heights indicated changes in junction properties with different fabrication conditions. The results of this study offer valuable perspectives for future research.Öğe Fine-tuning SnO2 films: Unleashing their potential through deposition temperature optimization by ultrasonic spray pyrolysis(Elsevier Sci Ltd, 2024) Sarıca, Emrah; Özcan, Hakan Bilal; Güneş, İbrahim; Terlemezoğlu, Makbule; Akyüz, İdrisIn 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.Öğe Flow rate-dependent properties of SnO2 thin films deposited by ultrasonic spray pyrolysis(Elsevier, 2024) Güneş, İbrahim; Sarıca, Emrah; Özcan, Hakan Bilal; Terlemezoğlu, Makbule; Akyüz, İdrisThis 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.Öğe Fluorine-doped tin oxide films via ultrasonic spray pyrolysis: Investigation of physical properties post-annealing and their potential for TCO applications(Elsevier, 2024) Güneş, İbrahim; Sarıca, Emrah; Bilgin, Vildan; Küçükarslan, Ayşe; Özder, SerhatIn 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.Öğe Fotovoltaik uygulamalar için CZTS tabakaların ultrasonik sprey piroliz yöntemi ile büyütülmesi ve optimizasyonu(Çanakkale Onsekiz Mart Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2022) Güneş, İbrahim; Bilgin, Vildan; Sarıca, EmrahCZTS ince filmlerinin fotovoltaik aygıt performansını iyileştirmek için kristal yapısının, olası ikincil faz oluşumunun, kusurların ve Cu/Zn katyon düzensizliği etkilerinin daha iyi anlaşılması gerekir. Bu doğrultuda, stokiyometrik olmayan (Cu-fakir ve Zn-Zengin) bir püskürtme çözeltisi farklı alttaş sıcaklıklarında (350 °C, 400 °C, 450 °C ve 500 °C) cam alttaşlar üzerine püskürtülerek kesterit CZTS ince filmleri elde edilmiştir. Sonrasında ise elde edilen CZTS ince filmlerinin opto-elektriksel özelliklerinin yanı sıra ikincil fazlar ve Cu/Zn katyon düzensizliği gibi yapısal homojensizlikler üzerine alttaş sıcaklığının etkisi deneysel olarak incelenmiştir. XRD ve Raman spektroskopisi analizleri ile çöktürülen ince filmlerin yapısal özellikleri araştırıldı. Raman spektrumlarına uygulanan Lorentzyen ters evrişimi ile 14 Raman titreşim modu tespit edildi. Ayrıca, bu modlara ait fazlardan CZTS'nin düzenli-kesterit fazı ile düzensiz-kesterit fazının birlikte kristalleştiği tespit edildi. XPS analizleri ile CZTS bileşiğini oluşturan elementlerin oksidasyon durumları belirlendi. EDS verileri stokiyometri-dışı model çerçevesinde değerlendirilerek baskın nokta kusurları tartışıldı. SEM ve AFM görüntüleri ile ince filmlere ait yüzey morfolojileri araştırıldı. Optik analizler çerçevesinde, bant aralıkları ve Urbach enerjilerinin alttaş sıcaklığındaki artışla düştüğü görüldü. Elektriksel analizler neticesinde tüm filmlerin p-tipi elektriksel iletkenliğe sahip olduğu ve elektriksel özdirenç değerlerinin 2.93x101-8.01x101 cm aralığında değiştiği tespit edildi. Bu tez çalışması, yüksek verimlilikli fotovoltaik uygulamalar için CZTS ince filmlerin fiziksel özelliklerinin alttaş sıcaklığına bağlı değişiminin yeni bir detaylı tartışmasını sunmaktadır.Öğe Plazma ile büyütülmüş hidrojenlenmiş amorf silisyum karbür ince filmlerin fotolüminesans özelliklerinin incelenmesi(Çanakkale Onsekiz Mart Üniversitesi, 2012) Güneş, İbrahim; Sel, KıvançBu çalışmada, 30 mW/cm2 (Düşük güç (DG)) ve 90 mW/cm2 (Yüksek güç (YG)) olmak üzere iki farklı radyo frekansı (RF) güç yoğunluğunda ve dört farklı karbon içeriğinde (x), plazma destekli kimyasal buhar biriktirme (PDKBB) sistemi ile büyütülmüş olan hidrojenlenmiş amorf silisyum karbür (a-SiCx:H) ince filmlerin fotolüminesans spektrumları incelendi ve ışıma mekanizmaları analiz edildi.Oda sıcaklığında ölçülen fotolüminesans spektrumlarına Gauss eğrileri uydurularak fotolüminesans maksimumları (EL) ve tam genişlik yarı maksimumları (?EL) hesaplandı ve morötesi-görünür bölge geçirgenlik spektroskopisi ile belirlenmiş olan optik enerjiler ve Urbach enerjileri ile karşılaştırılarak analiz edildi. Filmlerin, X-ışını foto-elektron spektroskopisi ile belirlenmiş olan karbon içeriğinin artması sonucunda EL ve optik enerjilerin orantılı olarak arttığı; bu artışın YG filmlerde DG filmlere kıyasla daha fazla olduğu gözlemlendi. a-SiCx:H filmlerin ışıma mekanizmaları, `elektron-fonon çiftleşmesi modeli' ve `statik düzensizlik modeli' çerçevesinde araştırıldı. DG filmler için elektron-fonon çiftleşmesi modelinin ve YG filmler için ise statik düzensizlik modelinin baskın model olduğu belirlendi. a-SiCx:H filmlerin oda sıcaklığındaki fotolüminesans spektrumları, empirik Gauss fonksiyonları ile tanımlanan iletim ve değerlik bant uzantı durum yoğunluklarının bileşke durum yoğunluğu yaklaşımı ile modellendi. Işıma modeli, ölçülen fotolüminesans spektrumlarına nümerik olarak uygulandı ve modelin deney verileri ile uyuştuğu görüldü.Öğe Sol-gel derived ZnO:Sn thin films and fabrication of n-ZnO:Sn/p-Si heterostructure(Elsevier B.V., 2021) Sarıca, Emrah; Güneş, İbrahim; Akyüz, İdris; Bilgin, Vildan; Ertürk, KadirIn 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)2·2H2O 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 × 100 Ωcm to 2.82 × 104 Ωcm 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.Öğe Tailoring the physical properties of ultrasonically spray pyrolyzed SnS thin films with silver doping(Springer, 2025) Güneş, İbrahim; Sarıca, Emrah; Bilgin, Vildan; Küçükarslan, AyşeIn this study, the effects of silver (Ag) doping on the structural, morphological, optical, and electrical properties of tin monosulfide (SnS) thin films were investigated. The films, undoped and doped with 3%, 6%, and 9% Ag, were deposited using the ultrasonic spray pyrolysis (USP) technique at a substrate temperature of 350 degrees C. X-ray diffraction (XRD) analysis confirmed a pi-SnS (cubic) structure with (400) preferred orientation for undoped and <= 6% Ag-doped films, while 9% doping induced amorphization due to severe lattice distortions. Morphological analyses revealed smooth, void-free surfaces, with average roughness increasing from 5.8 nm (undoped) to 19.6 nm (9% doping). Optical measurements showed that the band gap widened from 1.84 eV (undoped) to 2.47 eV (9% Ag-doped), and Urbach energy increased from 190 meV to 600 meV. Hall effect measurements confirmed p-type conductivity for all films. Resistivity ranged from 4.34 x 10(5) Omega cm to 9.48 x 10(5) Omega cm, carrier concentration varied between 2.7 x 10(12) cm(-3) and 5.6 x 10(12) cm(-3), while mobility decreased from 3.3 x 10(1) cm(2)/Vs to 2.0 x 10(1) cm(2)/Vs with increasing Ag doping. These findings demonstrate that Ag doping significantly influences the structural and optoelectronic behavior of SnS thin films, making them promising candidates for thin-film solar cells and optoelectronic applications.Öğe The Effect of Fe and Co doping on the Physical Properties of CdO Films Deposited by Ultrasonic Spray Pyrolysis(Springer, 2025) Demirselçuk, Barbaros; Güneş, İbrahim; Sarıca, Emrah; Kuş, Esra; Küçükarslan, Ayşe; Bilgin, VildanIn 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.
