Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Influence of Fluorine on Structural and Electrical Properties of VO2 Thin Films Deposited by Magnetron Sputtering
    (Elsevier Ltd, 2025) Akyurek, Bora; Cantas, Ayten; Demirhan, Yasemin; Ozyuzer, Lutfi; Aygun, Gulnur
    This study investigates whether fluorine-based thermal gel used during electrical measurements of vanadium oxide (VO2) films influences the structural, morphological, or compositional integrity of the films. High-quality VO2 films with a resistance ratio change of about 10(4) for metal-insulator transition were deposited by magnetron sputtering. During electrical characterization, VO2 film was heated from room temperature to similar to 370 K with a fluorine-based thermal gel usage to achieve better heat contact between the film and substrate holder. Structural and chemical properties were assessed through XRD, Raman, XPS, SEM, and energy dispersive spectroscopy imaging. XRD revealed diffraction peaks consistent with monoclinic VO2 confirming that the crystal lattice remains the same although fluorine based thermal gel was used. Raman spectra exhibited vibrational modes indicating that the phonon structure of VO2 was preserved despite fluorine gel usage. XPS results showed only a minor F 1s signal (2.8%) limited only to the film surface. SEM and EDS analyses further confirmed that surface morphology and elemental composition remained belonging to VO2 film. These findings demonstrate that the usage of fluorine-based thermal gel results in only a minimal surface interaction, thereby preserving intrinsic material properties of VO2 and supporting a potential usage for future device fabrication applications.
  • Article
    Citation - Scopus: 1
    Investigation of LiCoO2 Thin Films Grown Under Relatively Low Substrate Temperature for All Solid State Lithium Ion Battery Applications
    (Pergamon-elsevier Science Ltd, 2025) Ozcan, Polatkan; Esen, Nazlican; Cantas, Ayten; Ozyuzer, Lutfi; Ozdemir, Mehtap; Kosiel, Kamil; Aygun, Gulnur
    This study examines the effect of substrate temperature on the surface, structural and chemical properties of LiCoO2 (LCO) thin films deposited via magnetron sputtering. LCO thin films were grown for the purpose of being a cathode layer for all-solid-state lithium-ion batteries (ASSLIBs). Achieving crystalline LCO films at low substrate temperatures is advantageous for integration with flexible and temperature-sensitive substrates as well as minimizing energy consumption, which is highly important for industrial applications. In this work, LCO thin films were deposited on titanium-coated soda lime glass (SLG/Ti) at the substrate temperature ranging from room to 350 degrees C. Structural characterizations by XRD analyses confirmed that LCO thin films have (104) crystal orientation, which is critical for efficient lithium-ion transportation. SEM, Raman, and XPS analyses were used for further chemical and structural characterizations of grown LCO thin films. These analyses showed that LCO thin film grown at relatively low substrate temperature of 250 degrees C is a better growth condition when compared to others. Crystallization orientation (104) of LCO thin films is highly important for the potential usage of ASSLIBs technologies without any need of elevated temperatures. Moreover, results support the low-temperature adaption processes for applications like wearable electronics, offering safer and more sustainable solutions for future energy storage systems.
  • Conference Object
    Citation - Scopus: 2
    Magnetron Sputtering Deposition of Sb2se3thin Films: Physical Property Characterizations and Its Relevance for Photovoltaics
    (Institute of Electrical and Electronics Engineers Inc., 2020) Gundogan,S.H.; Ozyuzer,L.; Aygun,G.; Cantas,A.
    The absorber layer is a significant part of the solar cell configuration because of its role in determining the efficiency. Since the properties of the chalcogenides have been studied intensively, the Sb2Se3 material has come into prominence. In thin film technology, the most effective ways of increasing the performance are the rate of photon absorption, long material life, carrier efficiency and the quality of the interface. Sb2Se3 gets more attention than others due to its optoelectronic properties. Sb2Se3 has a suitable band gap (Eg), long term material stability, and a relatively simple composition with non-Toxic and earth abundant elements. All these features make Sb2Se3 a promising candidate for use as an absorber layer in thin film photovoltaics (PVs). In this study, Sb2Se3 films have been grown with DC magnetron sputtering method onto soda lime glass (SLG) substrates with different time durations. Morphological, structural, and optical properties of Sb2Se3 thin films were systematically investigated as a function of the thickness for photovoltaic applications. Our results indicate that the optical transmission, absorption behavior, and bandgap energy are strongly dependent on the thickness of the film. © 2020 IEEE.
  • Conference Object
    Citation - Scopus: 2
    The Effect of Ar Gas Flow Rate on Structure and Optical Properties of Magnetron Sputtered Sb2se3thin Films for Solar Cells
    (Institute of Electrical and Electronics Engineers Inc., 2020) Gundogan,S.H.; Ozyuzer,L.; Aygun,G.; Cantas,A.
    Recently, antimony selenide (Sb2Se3) absorber layer attracts so much attention in photovoltaic industry since it contains earth abundant, low cost and non-Toxic elements contrary to other chalcogenide based solar cells. In the present work, Sb2Se3 absorber films were grown by radio-frequency (RF) magnetron sputtering technique using binary single target and employing various argon flow rates, and then they were annealed under argon atmosphere inside a tubular furnace. Sb2Se3 thin films were investigated using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and UV-VIS NIR spectrophotometer. The effects of argon flow rate, one of the sputtering parameters, on the properties of the Sb2Se3 films were investigated. The significance of argon flow rate, that used during film deposition, on the observing of Se loss, antimony oxide formation and the change in the surface morphology was also addressed. We observed that the dominant crystal orientation varied with respect to argon flow rate. It was further detected that high argon flow rates cause the decomposition of Sb2Se3 structure and formation of antimony oxide phase. The overall analyses revealed that argon flow rate used while sputtering is effective in changing the structural, and optical properties of the Sb2Se3 thin films. © 2020 IEEE.