Thermionic Emission Properties of Oxide Based Nano-Structures

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Heydarian, Hesam | 2013

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 44245 (05)
University: Sharif University of Technology
Department: Electrical Engineering
Advisor(s): Rashidian, Bijan
Abstract:
For years, in thermionic emission, a great deal of scientists’s effort has been devoted to the search for low work function materials with high melting temperature. In this way, high brightness and long life are the central targets of emission material investigations. In addition, high current density and low power consumption are the guiding principles for some applications.
In first part of this thesis, basic electron emission theories, fabrication methods of thermionic emission, effect of different parameters on the electron emission properties of thermionic emitters and applications of them are investigated. After setting up fabrication methods of S type cathode, in the second part of thesis, tungsten pellets are sintered using electron beam evaporation systems and S type cathode are fabricated and as a result completely open prosity tungsten pellets are achieved. Improvements in methods, results and SEM images of different parts of the fabrication process are demonstrated. At the final stage, current density and electron emission I-V characteristics are measured
Keywords:
Thermionic Current ; Filed Emission ; Thermal Oxidation ; Oxide Based Nanostructures ; Thermionic Emission

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