Spintronics: Towards Room Temperature Ferromagnetic Devices via Mn and Rare Earth Doped GaN.

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dc.contributor.advisor Ki Wook Kim, Committee Member en_US
dc.contributor.advisor John M. Zavada, Committee Member en_US
dc.contributor.advisor Nadia A. El-Masry, Committee Co-Chair en_US
dc.contributor.advisor Salah M. Bedair, Committee Chair en_US
dc.contributor.author Luen, Melvyn Oliver en_US
dc.date.accessioned 2010-04-02T19:17:17Z
dc.date.available 2010-04-02T19:17:17Z
dc.date.issued 2010-03-08 en_US
dc.identifier.other etd-01042010-133521 en_US
dc.identifier.uri http://www.lib.ncsu.edu/resolver/1840.16/5659
dc.description.abstract Spintronics is a multidisciplinary field aimed at the active manipulation of spin degrees of freedom in solid-state systems. The goal being the understanding of the interaction between the particle spin and its solid-state environment, and the making of useful devices based on the acquired knowledge. If Moore's law is to continue, then we need to find alternatives to conventional microelectronics. Where conventional electronic devices rely on manipulating charge to produce desired functions, spintronic devices would manipulate both the charge flow and electron spin within that flow. This would add an extra degree of freedom to microelectronics and usher in the era of truly nanoelectronic devices. Research aimed at a whole new generation of electronic devices is underway by introducing electron spin as a new or additional physical variable, and semiconductor devices that exploit this new freedom will operate faster and more efficiently than conventional microelectronic devices and offer new functionality that promises to revolutionize the electronics industry. Long recognized as the material of choice for next-generation solid-state lighting, gallium nitride (GaN) also has proven uses in the field of high power, high frequency field-effect transistors (FETs). But its promise as a material system for spintronic applications may be its ultimate legacy. In this dissertation, the growth of gallium-manganese-nitride (GaMnN) compound semiconductor alloy was investigated through the use of an in-house built metal-organic chemical vapor deposition (MOCVD) reactor. Building on previous investigations of ferromagnetic mechanisms in GaMnN, where ferromagnetism was shown to be carrier mediated, a above room temperature ferromagnetic GaMnN i-p-n diode structure was conceived. This device proved to be the first of its kind in the world, where ferromagnetic properties are controlled via proximity of the mediating holes, upon voltage bias of adjacent structure layers. Simultaneously, post-growth diffusion of ferromagnetic, rare earth species into GaN template thin films also was investigated. Structural, electrical, optical and magnetic characterization of diffused films grown on sapphire was performed. Optimization of the conditions leading to the first successful diffusion of neodymium into GaN thin films, and the magnetic and optical studies that followed are detailed. A mechanism governing and conditions promoting ferromagnetism in rare earth (RE) doped GaN is proposed. The magnetic relationship between two similar and dissimilar rare earth elements, in a single GaN crystal are investigated. Finally, spin valve and magnetic tunnel junction devices based on the magnetic properties of RE-GaN thin films are investigated. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dis sertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject rare earth en_US
dc.subject MOCVD en_US
dc.subject Diffusion en_US
dc.subject manganese en_US
dc.subject room temperature en_US
dc.subject GaN en_US
dc.subject spintronics en_US
dc.title Spintronics: Towards Room Temperature Ferromagnetic Devices via Mn and Rare Earth Doped GaN. en_US
dc.degree.name PhD en_US
dc.degree.level dissertation en_US
dc.degree.discipline Electrical Engineering en_US

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