Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Pixel Array Application of High Temperature Superconducting Ybco Transition Edge Infrared Bolometers(Izmir Institute of Technology, 2009) Pekerten, Barış; Abukay, Doğan; Abukay, Doğan; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this thesis, we patterned pregrown epitaxial YBCO thin films on MgO, LAO and STO substrates into meander shaped high-Tc superconducting transition edge monolithic bolometers. We set up and automatized the electrical characterization processes of the bolometers. We also measured the bolometric response of the meanders to red and nearinfrared light and fit them to theoretical models in literature. We compared the single pixel bolometric responses to literature and found that our results are similar to or better than the results for similar devices in the literature.We also patterned staring arrays (focal plane arrays) and explored the resolution limit put in place by thermal crosstalk. We compared the measured crosstalk to theory and found a very good agreement. We quantified the crosstalk for our pixels. We then explored substrate etching method to decrease crosstalk via thermal isolation.Master Thesis Fabrication of Lu Doped Ybco Thin Films by Pulsed Laser Deposition Technique and Their Characterization(Izmir Institute of Technology, 2010) Sezer, Bahtiyar Şirvan; Abukay, Doğan; Abukay, Doğan; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyNearly twenty years ago YBCO was the first superconductor discovered with a transition temperature above the boiling point of liquid nitrogen, the .fascinating. limit for high temperature superconductivity. From the day forward, the interest in this ceramic compound has not diminished. YBCO is one of the most promising materials for the application of high temperature superconductors (HTS) because it is able to carry a technically useful current density in applied fields at 77 K. A lot of experiments guided to investigate the basic properties of the HTS and to further the theoretica understanding of them also used YBCO, because this progress has been achieved in the preparation of bulk samples, and especially thin films deposited by a various methods. The aim of the experimental investigation presented in this thesis was to produce high quality epitaxial Lutetium doped YBCO thin films on MgO substrates prepared by pulsed laser deposition. For this purpose, bulk Lu2O3 powder was mixed into YBCO by using solid-state reaction method and pressed to make a stoichiometric target for PLD process. KrF excimer laser was worked at 14 Kv with repetition rates ranging from 3 to 5 Hz to deposited Y0.9Lu0.1Ba2Cu3O7-. thin films at a substrate temperature of 800 oC. The surface of the films were characterized by employing XRD, SEM, EDX and AFM techniques.Master Thesis Fabrication of Ybco Thin Flims by Pulsed Laser Deposiyion Technique and Their Charcterization(Izmir Institute of Technology, 2010) Tozan, Şerife; Abukay, Doğan; Abukay, Doğan; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyThis thesis focuses on pulsed laser deposition (PLD) system, fabrication of high temperature superconducting YBCO thin films and their characterization. In this study, the electrical and structural studies performed on laser deposited YBCO films have shown that films produced by PLD. The thin films were characterized in detail by employing structural XRD, SEM, EDX and AFM and electrical ( R-T) measurements. During this work, pulsed laser deposition system used to grow superconducting thin film on MgO single crystal substrate. Firstly PLD system was carried out by using different growth parameters. Deposited films was cooled down in situ under an oxygen atmosphere at a given pressure. The deposition tecnique has emerged as a very powerful method to make composition and microstructure controlled superconducting YBCO films.Thanks to rapid heating and evaporation of the target and interaction of the laser beam with evaporated materials leading to formation of a high temperature plasma PLD system is different from other thin film growth system.However, major problem was particulates emmission which was shown SEM,we solved this problem by chaning distance between target and substrate, and laser power. Furthermore Electron Dispersive X-Ray Spectroscopy (EDX) method was used to identify the chemical contents of the films.The relation between critical temperature and oxygen deficieny was investigated by means of electrical resistance R(T) and x-ray diffraction measurements.Finally, our results were compared to literature and explanied similarites.