Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
Browse
2 results
Search Results
Master Thesis Electrical Surface Modification and Characterization of Metallic Thin Films Using Scanning Probe Microscope (spm) Nanolithography Method(Izmir Institute of Technology, 2009) Büyükköse, Serkan; Okur, Salih; Okur, Salih; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyThis thesis focuses on local oxidation of metallic thin films using atomic force microscopy (AFM). The primary aim of this thesis is to investigate the growth kinetics of oxide forms of these metallic materials and characterize the resulted oxide structures. In this study, tantalum, hafnium and zirconium thin films were used to be oxidized via AFM. During this work, metallic thin films were grown on Si and SiOx substrates with DC magnetron sputtering method. Thin films were characterized via x-ray diffraction, scanning electron microscopy and atomic force microscopy. Oxidation experiments were performed under different environmental conditions to explore the effect of influential parameters; such as bias voltage, oxidation time and relative humidity, and line shape oxide structures were created on metallic films. Dimensional analysis of created oxide structures was carried out measuring height and line-width of oxide lines as a function of applied voltage, oxidation time and relative humidity. In addition to the dimensional analysis, electrical characterization of metal-oxides was performed via AFM electrical characterization methods which are two terminal I-V measurements, electric force microscopy and spreading resistance measurements. At the end of the thesis, the capability of this method to create lateral metal-oxide-metal junction was shown oxidizing a tantalum stripe and performing in-situ resistance measurement. Patterning of tantalum stripes was accomplished by standard photolithography process and lift-off technique.Master Thesis Characterization of Modified Ito Anode Surfaces With 4 [3-Methylphenyl) Phenyl) Anino] Benzoic Acid for Oled Applications(Izmir Institute of Technology, 2011) Yağmurcukardeş, Nesli; Okur, Salih; Okur, Salih; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyThis thesis focuses on to improve OLED characteristics of fabricated devices by modifying the ITO (anode) surface using novel carboxylic acid based molecule 4-[(3-methylphenyl)(phenyl)amino]benzoic acid (MPPBA). In this study, commercial ITO substrates were used as anodes. To modify the ITO surface, etched ITO substrates were kept in 1mM MPPBA-ethanol solution. As a hole transport layer (HTL), N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) or N,N'-Di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl)-4,4'-diamine (NPB) small molecules were deposited using an organic evaporator system under the vacuum of 10-6 Torr. Finally, as a cathode contact layer, aluminum thin film of 120 nm was deposited on top of the fabricated organic thin film layers. The final structure of the devices was obtained as ITO /SAM (2nm) /HTL (50nm) /Al (120nm). The current-voltage characteristics of devices of unmodified bare ITO and MPPBA modified ITO substrates were analyzed by using the space charge limited current approach and Thermionic Schottky Emission Models. Additionally, surface characterizations of the SAM modified thin films were carried out using Quartz Crystal Microbalance (QCM), Atomic Force Microscopy (AFM), Kelvin Probe Force Microscopy (KPFM), X-ray Photoelectron Spectroscopy (XPS), Cyclic Voltammetry (CV) and Ultraviolet-visible Absorption Spectroscopy (UV-Vis) techniques. The obtained results reveal that the modification of the ITO surface with MPPBA molecules reduces the barrier height difference between the Fermi level of the anode and HOMO level of the HTL. Hence the hole injection increases while the turn-on voltage decreases. As a result of this process OLED characteristics were improved by using the MPPBA SAM molecules.