Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 10 of 10 for “"oxygen interstitials"”.
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A first principles study of defects in titanium: interaction of twin boundaries with dislocations and oxygen interstitials
… of hcp metals such as titanium. In addition, oxygen greatly affects both strength and twinning in titanium. Predictive models of strength and twinning rely on understanding of the underlying atomic scale mechanisms which are best captured through computer simulations. While recent …
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Oxygen self-diffusion via a mobile intermediate species in rutile titania
… titania allows for facile injection of a mobile oxygen intermediate other than the doubly-charged oxygen vacancy. Characteristic exponential tail profiles coupled with the observation of a positive oxygen partial pressure dependence on isotopic oxygen diffusion in rutile suggests that the …
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Surface-mediated mechanisms for defect engineering in zinc oxide
… zinc oxide, the concentration and diffusion of oxygen point defects, like interstitials and vacancies, play a central role in various physical phenomena, such as gas sensing, bipolar switching, photoluminescence and photocatalysis. Defect engineering in metal oxides aims at manipulating material …
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Surface-mediated mechanisms for defect engineering in metal oxides
… mechanisms would enable us to engineer oxygen and cationic point defects in metal oxides. The present work involves both experimental (isotope gas-solid exchange) and computational (ab initio quantum calculations, continuum models) efforts aimed at understanding the (1) injection of …
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Surface chemistry to control bulk reaction dynamics of native point defects in rutile titanium dioxide
… diffusion of cations and anions, in the form of interstitials and vacancies, plays a large role in the performance of these materials for gas sensing, photocatalysis, microelectronics and photovoltaic cells. The ability to control the properties of semiconductors through defect manipulation, or …
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Enhanced Charge Transport and Cell Performance of an Inverted Organic Solar Cell Via UV-ozone Treatment of ZnO
… treated ZnO surface indicated diffusion of oxygen species inside the film, improvement in crystallinity of the film and introduction of oxygen interstitials inside the ZnO film. An inverted solar cell, based on PBDTTT-C-T:PC70BM as the active layer, using UV ozone treated ZnO as an electron …
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Discovery of mechanisms and methods for surface-based defect engineering in oxide semiconductors using liquid water
… processes with a novel approach involving oxygen-ion diffusion in bulk and oxygen-ion exchange through the surface (injection/annihilation) in oxides under experimental annealing conditions and atmospheric air. The present work also introduces post-synthesis methods to control defect …
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Controlling properties of functional oxides by tuning oxygen defect chemistry
Oxygen defects are essential building blocks for properties and functionalities of oxides, including electrical conductivity, magnetism, ferroelectricity as well as catalytic and electrocatalytic activity. Therefore, fundamental understanding of how to tune the oxygen defect chemistry is essential …
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New mechanisms for defect engineering in titanium dioxide
… metal oxide semiconductors. Through isotopic oxygen bulk diffusion studies done in an ultrahigh vacuum chamber, it has been observed that having a surface free from contamination increases the self-diffusion of oxygen in titanium dioxide. Photo-illumination effects were also observed for the …
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Multiscale Modeling of Effects of Solute Segregation and Oxidation on Grain Boundary Strength in Ni and Fe Based Alloys
… GBs, both substitutional and interstitial oxygen atoms of different concentrations are inserted at three Ni GBs: Σ3(111) coherent twin, Σ3(112) incoherent twin, and Σ5(210). Simulation results show that the GB strength decreases almost linearly with the increasing oxygen coverage at all …