The mechanism for the room temperature magnetic coupling and electric conduction in oxide diluted magnetic semiconductors (DMS) has been studied simultaneously on the Co:ZnO thin film by utilization of the electric field effect. We find that the carriers are bound on a defect in a radius much larger than the bounded magnetic polaron (BMP) radius, and can move by the variable range hopping (VRH) over a relative small distance. Therefore, a concentric bounded model consisting of a concentric localization configuration with a limited carrier VRH capability was proposed. In this model, the carriers localized around defects couples strongly with the doped magnetic ions forming a BMP in the inner sphere and can only itinerate with no spin coherence in the outer shell. Carriers can hop either by spin-polarized or by spin-independent VRH directly between or not directly between adjacent inner spheres, respectively. This model can explain both the electric and magnetic properties of the oxide DMS, and depicts an evolution of electric and magnetic properties associated with defect concentration.

Thesis (Ph. D.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 6, 2007) Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2007. / Includes bibliographical references (leaves 181-186).

Thesis (M.S.)--University of Delaware, 2008. / Principal faculty advisor: S. Ismat Shah, Dept. of Materials Science. Includes bibliographical references.

No description available.

Rao, Yangyan = 氧化鋅的納米結構以及准一維氧化鋅稀磁半導體的合成及研究 / 饒洋燕. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / Rao, Yangyan = Yang hua xin de na mi jie gou yi ji zhun yi wei yang hua xin xi ci ban dao ti de he cheng ji yan jiu / Rao Yangyan. / Abstract --- p.1 / 摘要 --- p.3 / Acknowledgments --- p.4 / Table of contents --- p.5 / Chapter Chapter 1 --- Introduction --- p.7 / Chapter 1.1 --- Zinc oxide --- p.7 / Chapter 1.2 --- Mn doped ZnO diluted magnetic semiconductors --- p.7 / Chapter 1.3 --- Motivations --- p.9 / Chapter 1.4 --- Our Work --- p.10 / Chapter 1.5 --- Overview of the thesis --- p.11 / References --- p.11 / Chapter Chapter 2 --- Experimental set-up and conditions --- p.15 / Chapter 2.1 --- Chemical Vapor Deposition --- p.15 / Chapter 2.1.1 --- Key Steps in Chemical Vapor Deposition --- p.15 / Chapter 2.2 --- Experiments on the synthesis of ZnO nanostructures --- p.16 / Chapter 2.2.1 --- Set-up --- p.17 / Chapter 2.2.2 --- Growth mechanism --- p.18 / Chapter 2.2.3 --- Experimental conditions --- p.20 / References --- p.23 / Chapter Chapter 3 --- Characterization of pure ZnO --- p.25 / Chapter 3.1 --- Morphology of ZnO nanowires --- p.25 / Chapter 3.2 --- Lattice structure --- p.30 / Chapter 3.3 --- Photoluminescence property (PL) --- p.32 / Chapter 3.4 --- Lattice dynamics´ؤRaman spectra --- p.33 / References --- p.35 / Chapter Chapter 4 --- Properties of Mn doped ZnO nanowires --- p.37 / Chapter 4.1 --- Morphology and composition --- p.37 / Chapter 4.2 --- Lattice structure of Mn-doped ZnO --- p.40 / Chapter 4.3 --- Lattice dynamics´ؤRaman study of Mn-doped ZnO nanowires --- p.46 / References --- p.48 / Chapter Chapter 5 --- Magnetic properties of Mn doped ZnO nanowires --- p.50 / Chapter 5.1 --- Theory of DMS --- p.50 / Chapter 5.2 --- Magnetic results of Mn doped ZnO nanowires --- p.52 / Chapter 5.2.1 --- Paramagnetism of Mn doped ZnO --- p.52 / Chapter 5.2.2 --- Ferromagnetism of Mn doped ZnO --- p.58 / References --- p.65 / Chapter Chapter 6 --- Conclusions --- p.67

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 163-175).

We have grown Ga1-xMnxN films on c-sapphire substrate by plasma-assisted MBE with different Mn fluxes. The films are characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), electron backscatter diffraction (EBSD), high¡Vresolution X-ray diffraction (HR-XRD), Raman scattering, photoluminescence (PL), cathodoluminescence (CL), transmission spectra, reflection spectra and X-ray photoelectron spectroscopy (XPS). The SEM images show films thickness between 550 to 850 nm and EBSD indicates samples normal direction is c-axis. EDS spectra show the Mn is present in GaMnN samples. According to XRD and Raman scattering, Mn element occupying Ga site on GaN and Mn-N clusters phase coexist on films. From transmission and reflection spectra, stronger absorption at about 1.5 eV and 1.8 eV to 3.4 eV absorption band are found. The PL and CL show GaN band gap at 3.4 eV and blue band from 2.4 eV to 3.3 eV maybe due to defect level. Finally, the XPS spectra indicate Mn acceptor level is contributed to Mn+2 or Mn+3 states.

Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisor: John Q. Xiao, Dept. of Physics and Astronomy. Includes bibliographical references.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 63-66). Also available in electronic version. Access restricted to campus users.