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Annealing studies on the structural and magnetical properties of Co implanted ZnO single crystalZou, Lanlan., 邹兰兰. January 2012 (has links)
As a wide band gap semiconductor, Zinc Oxide (ZnO) has recently attracted considerable attention due to its wide applicability. Transition metal (TM) doped ZnO is one of the most intensive research field in the last decade because of its possible application in spintronics devices. The Co-implanted ZnO has been considered as one of the most promising candidate in the field of diluted magnetic semiconductor (DMS).
In this study, the magnetic and structural properties of Co-implanted ZnO single crystal were investigated. ZnO single crystals were implanted with 100 keV-Co ions at 300K with a fluence of 1014cm-2and subsequently annealed at 750oC and 900oC respectively. The samples were studied by secondary ion mass spectrometry, X-ray diffraction, photoluminescence, X-ray photoemission spectroscopy and vibrating sample magnetometer. The as-implanted sample seemed to be phase pure while the spinel secondary phase ZnCo2O4 was present in 750oC and 900oC samples showed trace ofCo3O4,Zn0.52Co2.48O4 and metallic Co cluster. All the samples exhibited ferromagnetism at room temperature in low field region, and the magnetic moment was found to decrease and increase after the heat treatment. In high field region, typical paramagnetism was the dominating magnetic property. More than one ferromagnetic mechanism is involved to explain the experimental results. / published_or_final_version / Physics / Master / Master of Philosophy
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Annealing of GaA1As double heterostructures with homogeneous ruby laser lightBrett, Michael Julian January 1981 (has links)
The output from a ruby laser was homogenized, and used to laser anneal the active layer of GaA1As double heterostructure wafers in an attempt to improve the radiative efficiency of the active layer. At anneal energies exceeding the estimated threshold for melting of the active layer, the radiative efficiency was reduced by a factor of two. Subsequently, semiconductor laser diodes fabricated from laser annealed heterostructures performed much worse than those fabricated from unannealed heterostructures. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
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X-ray topography of laser annealed ion implanted silicon crystalsPrieto, Argenis January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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Studies of molecular mobility in oriented polypropylene by vapor diffusion and ESR techniques.January 1983 (has links)
by Ma Tak-lun. / Bibliography: leaves 68-69 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983
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Effect of annealing on the structure and properties of barley starches /Waduge, Renuka Nilmini, January 2005 (has links)
Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Restricted until October 2007. Bibliography: leaves 133-164.
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The two gallium vacancy-related defects in undoped gallium antimonideMa, Shun-kit, Martin., 馬信傑. January 2004 (has links)
published_or_final_version / abstract / toc / Physics / Master / Master of Philosophy
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Boron doping of diamond powder by enhanced diffusion and forced diffusion : diffusion concentrations, mechanical, chemical and optical properties /Golshani, Fariborz, January 1997 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 91-94). Also available on the Internet.
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Boron doping of diamond powder by enhanced diffusion and forced diffusion diffusion concentrations, mechanical, chemical and optical properties /Golshani, Fariborz, January 1997 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 91-94). Also available on the Internet.
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The two gallium vacancy-related defects in undoped gallium antimonideMa, Shun-kit, Martin. January 2004 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.
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Controlling the Properties of Modular MaterialsRussell, Jake Carter January 2021 (has links)
I introduce the concept of modular materials and give a brief overview of their history and widespread occurrence in many areas of chemistry. I then discuss some of the many applications in which modular materials may find a use and link them to the following chapters. Chapter 1 describes the layered superatomic material Re₆Se₈Cl₂ and the induction of superconducting behavior in its single crystals through a current annealing technique. We suggest that this superconductivity arises through electron doping, as a result of dissociation of the apical Cl atoms from the clusters.
Chapters 2-4 explore other types of superatomic materials and their properties, centered on the well-studied Co₆X₈ unit, where X is a chalcogen. Chapter 2 describes a Co₆Te₈-C₇₀ co-crystal that exhibits multiple phase changes with temperature, each giving rise to unique electronic, thermal, and structural properties. Chapter 3 describes a series of “solid solutions” of Co₆Se₈ and Cr₆Te₈ units. By varying the ratios of the component superatoms, transport properties of the crystals can be tuned, and unexpected behavior arises as a result of structural heterogeneity. Chapter 4 presents another study of Co₆Se₈ co-crystallized with rod-shaped C₁₄₀ fullerenes. The packing and electronic properties are found to be greatly affected by the degree of solvent inclusion.
Chapters 5-6 examine another class of cluster-based materials: atomically precise gold nanoparticles. In Chapter 5 the cluster Au₂₁ is shown to self-assemble depending on the surface “hook” ligands, with corresponding differences in electronic transport. Chapter 6 discusses an interesting phase transition and thermally-induced hysteresis observed in crystals of the Au₁₀₃ cluster, also related to the surface ligand configuration.
Chapters 7-8 take a different approach to modular materials, in the form of organic polymers. Using the robust, electroactive pigment molecule PDI as a common building block, we synthesize extended networks that are found to be exceptional pseudocapacitive energy storage materials. Chapter 7 introduces the honeycomb-shaped PDI-triptycene polymer, establishes its pseudocapacitive nature, and explores the role of cyclization in tuning its behavior. Chapter 8 expands upon the concept by combining PDI with hexaazatrinaphthalene to create a “contorted” network with best-in-class energy storage performance. In addition to in-depth kinetic analyses to elucidate the mechanism of storage, we fabricate two-electrode cells to demonstrate the material’s potential in real-world devices.
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