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Full-Text Articles in Engineering
Point Defects In Lithium Gallate And Gallium Oxide, Christopher A. Lenyk
Point Defects In Lithium Gallate And Gallium Oxide, Christopher A. Lenyk
Theses and Dissertations
Electron paramagnetic resonance (EPR), Fourier-Transform Infrared spectroscopy (FTIR), photoluminescence (PL), thermoluminescence (TL), and wavelength-dependent TL are used to identify and characterize point defects in lithium gallate and β-gallium oxide doped with Mg and Fe acceptor impurities single crystals. EPR investigations of LiGaO2 identify fundamental intrinsic cation defects lithium (V−Li) and gallium (V2−Ga) vacancies. The defects’ principle g values are found through angular dependence studies and atomic-scale models for these new defects are proposed. Thermoluminescence measurements estimate the activation energy of lithium vacancies at Ea = 1.05 eV and gallium vacancies at Ea > 2 …
Neutron Radiation Effects On Ge And Gesn Semiconductors, Christopher T. O'Daniel
Neutron Radiation Effects On Ge And Gesn Semiconductors, Christopher T. O'Daniel
Theses and Dissertations
Two different semiconductor materials received neutron radiation for assessment of radiation damage. The two materials are undoped bulk Ge and epitaxial Ge0.991Sn0.009, which is doped heavily with phosphorous. At room temperature, the Ge sample has direct and indirect bandgaps at 0.78 eV and 0.66 eV, respectively. The Ge0.991Sn0.009 sample has direct and indirect bandgaps at 0.72 eV and 0.63 eV, respectively. Two samples of each material were exposed to research reactor neutrons, delivering a 1 MeV equivalent neutron fluence of 2.52 × 1015 n/cm2. In order to assess the radiation …
Surface Oxidation Study Of Uranium Dioxide Under Wet And Dry Conditions, Gary T. Brett
Surface Oxidation Study Of Uranium Dioxide Under Wet And Dry Conditions, Gary T. Brett
Theses and Dissertations
The surface oxidation of pressed uranium dioxide (UO2) powder under controlled environmental conditions and the oxidation and reduction of pressed uranium trioxide (UO3) powder are presented. This is a continuing research project in the investigation of the oxidation of UO2 powder using Photoluminescence (PL) Spectroscopy. UO2 particles exposed to the ambient atmosphere will oxidize into a number of chemical complexes (specifically hydrates, hydroxides, and carbonates). During certain of these oxidation processes, the uranium ion can lose two of its electrons and change from uranous (UIV+) to uranyl (UVI+). This research …