Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Author: search.filters.author.Özdemir, MehtapWoS Q: search.filters.wosQuartile.Q1

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 20
    Citation - Scopus: 23
    Surface Free Energy and Wettability Properties of Transparent Conducting Oxide-Based Films With Ag Interlayer
    (Elsevier, 2021) Özbay, Salih; Erdoğan, Nursev; Erden, Fuat; Ekmekçioğlu, Merve; Rakop, Büşra; Özdemir, Mehtap; Aygün, Gülnur; Özyüzer, Lütfi
    ITO, ZTO, AZO and Ag are commonly used in transparent conducting oxide (TCO)/metal/TCO electrodes to form multilayered thin films on a suitable substrate. A detailed surface free energy (SFE) knowledge of these films is critical to design desirable TCO-based sandwich structures. In this study, TCO/Ag/TCO multilayer thin films were coated onto glass substrates using ITO, ZTO, AZO and Ag targets by magnetron sputtering. The wettability properties of TCO, Ag interlayer and TCO/Ag/TCO were evaluated by contact angle measurements of seven different liquids having various surface tension values. The dispersive and polar components of SFE were calculated using geometric and harmonic mean approaches. The acidic and basic components of SFE were calculated using van Oss-Chaudhury-Good method. Following this, the work of adhesion values between TCO films and Ag interlayer were estimated using SFE values of the films. The results show that the SFE components of the surfaces differ depending on the TCO type, the total SFE values of TCO/Ag/TCO films were lower than that of TCO films, and AZO/Ag adhesion is stronger than the other TCO/Ag structures. The reasons behind these differences were discussed by evaluating the SFE, XRD, AFM and SEM analysis simultaneously.
  • Article
    Citation - WoS: 39
    Citation - Scopus: 46
    Surface Free Energy Analysis of Ito/Au Multilayer Thin Films on Polycarbonate Substrate by Apparent Contact Angle Measurements
    (Elsevier, 2020) Özbay, Salih; Erdoğan, Nursev; Erden, Fuat; Ekmekçioğlu, Merve; Özdemir, Mehtap; Aygün, Gülnur; Özyüzer, Lütfi
    A detailed surface free energy (SFE) knowledge of transparent conducing oxide (TCO)/metal/TCO electrodes is necessary for their applications related to surface wettability. However, SFE analysis of these surfaces has not been performed systematically previously. In this study, ITO and ITO/Au/ITO multilayer thin films were coated onto O-2 plasma treated polycarbonate (PC) substrates by magnetron sputtering. The wettability characteristics of untreated PC, O-2 plasma treated PC, ITO, Au interlayer, and ITO/Au/ITO multilayer thin films were evaluated by apparent contact angle measurements of nine different test liquids having various surface tensions. Following this, Lifshitz-van der Waals, acidic, basic, dispersive, and polar components of SFE were calculated using acidbase, geometric and harmonic mean approaches. In the present study, in which the significance of calculation methods and selected liquid pairs on SFE parameters were investigated, the effect of Au interlayer presence on SFE parameters were also evaluated simultaneously. The results showed that the total SFE values of ITO/Au/ITO multilayer thin films were found to be higher than that of ITO surface. The reasons behind this difference were discussed in terms of SFE components obtained using various liquid pairs by different methods. The results were also supported with XRD, XPS, AFM, and TEM analysis.
  • Article
    Citation - WoS: 31
    Citation - Scopus: 33
    The Controllable Deposition of Large Area Roll-To Sputtered Ito Thin Films for Photovoltaic Applications
    (Elsevier, 2020) Demirhan, Yasemin; Köseoğlu, Hasan; Türkoğlu, Fulya; Uyanık, Zemzem; Özdemir, Mehtap; Aygün, Gülnur; Özyüzer, Lütfi
    In the present study, using a large area roll-to-roll DC magnetron sputtering system deposition of ITO thin films on polyethylene terephthalate (PET) substrates were achieved. In order to investigate the effect of growth conditions on the film properties all through the deposition process, optical emission spectroscopy (OES) analysis have been accomplished in a governable way. The consequences of Oxygen partial pressure and film thickness on electrical, and optical properties of the films were determined. It was shown that the intensity of optical emission peaks are subjected to the discharge power and as well as the O-2/Ar flow ratio. Large area, uniform ITO films with relatively high transparency and low electrical resistivity (R(2)(<)50 Omega/sqr) were succesfully deposited on PET substrates. The significance of both the figure of merit (FOM) and the optical band gap values on the performance of different TCO thin films were addressed. In this work, the obtained results suggest that the overall performance is sufficient to implement the ITO films in photovoltaic and OLED applications. (C) 2019 Elsevier Ltd. All rights reserved.