Physics / Fizik

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

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Author: search.filters.author.Tarı, SüleymanWoS Q: search.filters.wosQuartile.Q2

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  • Article
    Citation - WoS: 35
    Citation - Scopus: 37
    Modification of Ito Surface Using Aromatic Small Molecules With Carboxylic Acid Groups for Oled Applications
    (Elsevier Ltd., 2011) Havare, Ali Kemal; Can, Mustafa; Demiç, Şerafettin; Okur, Salih; Kuş, Mahmut; Aydın, Hasan; Yağmurcukardeş, Nesli; Tarı, Süleyman
    4-[(3-Methylphenyl)(phenyl)amino]benzoic acid (MPPBA) was synthesized in order to facilitate the hole-injection in Organic Light Emitting Diodes (OLED). MPPBA was applied to form self-assembled monolayer (SAM) on indium tin oxide (ITO) anode to align energy-level at the interface between organic semiconductor material (TPD) and inorganic anode (ITO) in OLED devices. The modified surface was characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). KPFM was used to measure the surface potential and work function between the tip and the ITO surface modified by SAM technique using MPPBA. The OLED devices (ITO/MPPBA/TPD/Alq3/Al) fabricated with SAM-modified ITO substrates showed lower turn-on voltages and enhanced diode current compare to the OLED devices fabricated with bare ITO substrates.
  • Article
    Effect of Ta Buffer Layer and Tao X Barrier Thickness on the Evolution of the Structural and Magnetic Properties of the Fe/Tao X /Co Trilayers
    (Springer Verlag, 2010) Tokuç, Hüseyin; Tarı, Süleyman
    Fe/TaO x /Co trilayers were grown on Si(100)/SiO2 substrates and on tantalum buffer layers by a high vacuum magnetron sputtering system. The effects of both Ta buffer layer and tantalum-oxide barrier layer thickness on the structural and magnetic properties and the coupling of the ferromagnetic layers have been studied. It was observed that Ta improves the structural properties of the Fe layer resulting in an increased coercive field. For a barrier thickness of 4 nm a weak decoupling starts to appear between the ferromagnetic layers and a clear step formation is observed with increasing thickness. The minor hysteresis loops predict an interlayer coupling for thin barriers. The annealing of trilayers up to 250°C shows an increased coercivity for only the Fe layer. Annealing further at 400°C has the opposite effect of decreasing the coercivity, indicating intermixing at the interfaces of the Fe. The refractive index of the insulator barrier shows that the barrier layer is not totally in the form of tantalum-pentoxide. © 2009 Springer-Verlag.