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Showing 1 to 20 of 47 for “"oxygen vacancy"”.
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Development of Kinetic Monte Carlo Code to Study Oxygen Mobility in Lanthanum-doped Ceria
… a generalized Kinetic Monte Carlo code to study oxygen mobility in lanthanum-doped cerium oxide, and to demonstrate this code as a validation tool by simulating oxygen diffusion and comparing the results with experimental data to confirm the so-called lanthanum trapping effect. Molecular Statics …
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Linear-Scaling Density Functional Theory and Theoretical Electron Energy Loss Spectroscopy Investigations of Surfaces and Defects in Nanomaterials
… is used to predict the spectra associated with oxygen vacancy defects in the anatase (101) surface. These spectra are found to agree with the limited experimental data available. EEL spectra for nitrogen dopants in anatase are also predicted, based on literature geometries for these. The …
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Structure-Sensitivity of CO Oxidation Over Supported Pt Catalysts in the Subnanometer Regime and Its Origin
… pathways proceed with the involvement of oxygen adatoms directly provided by O2 dissociation, and not lattice oxygen, leading to very low turnover frequency. We then show that CO oxidation activity increases by 10-fold and 60-fold as average Pt size increases to 0.9 nm and 1.8 nm, …
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Synthesis and Electrochemical Performance of Lithium Lanthanum Titanate Solid-state Electrolyte
… developed: spark plasma sintering technology, oxygen vacancy manipulation and SiO2 doping. Spark plasma sintering technology enhances the processing methodology of LLTO to prevent lithium-ions loss at grain boundary, thus improving the grain boundary conductivity of LLTO to 1.624×10-6 S/cm. …
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ENGINEERING NI/AL2O3 CATALYSTS BY ATOMIC LAYER DEPOSITION FOR METHANE REFORMING
… MgO could introduce surface oxygen and enhanced the adsorption of CO<sub>2</sub>.</p> <p>ALD technique could effectively deposit highly dispersed Ni NPs (average size of 4.3 nm) on multiple 20-cm long four-channel α-Al<sub>2</sub>O<sub>3</sub> hollow fibers for DRM. The design …
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Mechanisms, Conditions and Applications of Filament Formation and Rupture in Resistive Memories
… mechanisms, conditions and applications of oxygen vacancy (Vo) filament formation in resistive memories. By studying the behavior of conductive Vo nanofilaments in several metal/oxide/metal resistive devices of various thicknesses of oxides, a resulting model supported by the data postulates …
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Systematics of bond length and radii variations in fluoride and silicate molecules and crystals
… of these films. It is noted that the presence of oxygen vacancies and their entrapment at the electrode-ferroelectric interfaces are the sources of the degradation phenomena. Attempts were made in this study to solve these problems: 1) by minimizing oxygen vacancy entrapment at the interfaces by …
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Electrical properties of doped and undoped PZT thin films prepared by a sol-gel method
… of these films. It is noted that the presence of oxygen vacancies and their entrapment at the electrode-ferroelectric interfaces are the sources of the degradation phenomena. Attempts were made in this study to solve these problems: 1) by minimizing oxygen vacancy entrapment at the interfaces by …
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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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Non-adiabatic electron-ion dynamics in semiconductors under ionizing particle irradiation
… impact, to ion diffusion. Our results on neutral oxygen vacancy in MgO show that the enhancement in atomic diffusion can be three orders of magnitude, given large enough concentration of oxygen vacancy and ion beam flux. Such significant enhancement happens at the low velocity regime that no …
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External field effects on electronic and ionic defects in functional oxides: Experiments and simulations
… the nonlinear dielectric response of neutral oxygen vacancies, composed of strongly localized electrons at an oxygen vacancy site, in perovskite oxides of the form ABO₃. Our approach implements a computationally-efficient local Hubbard U correction in density functional theory simulations. …
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First-Principles Study of Band Alignment and Electronic Structure at Metal/Oxide Interfaces: An Investigation of Dielectric Breakdown
… (Al/c-SiO2) interface. Point defects, such as oxygen vacancy (VO) and hydrogen impurity (IH), are introduced into the Al/c-SiO2 interface to study the effects on band offset and electronic structure caused by point defects at metal/oxide interfaces. It is shown that the bonding chemistry at …
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Nonvolatile and Volatile Resistive Switching - Characterization, Modeling, Memristive Subcircuits
… resistive switching devices. Both Cu and oxygen vacancy nanofilaments can conduct current according to the polarity of bias voltage. The volatile resistive switching phenomenon has been observed on Cu/TaOx/delta-Cu/Pt devices and explained by a flux balancing model. The resistive devices …
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Effects of hydrogen uptake and yttrium doping on the oxidation of zirconium-yttrium alloys
… work coupled with a computational study of oxygen, electron, and hydrogen diffusion. Experiments focused on the oxidation of 0.01-1 wt% yttrium in pure zirconium samples and the characterization of the resultant oxides and hydrides. A thermogravimetric analysis instrument was used to collect …
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Electrochemical and Modelling Studies on Simulated Spent Nuclear Fuel Corrosion under Permanent Waste Disposal Conditions
… defects, enhanced diffusion of OI (interstitial oxygen)to deeper locations and destabilization of the fluorite lattice. A further investigation of the doping effect was performed on a series of (U1−yGdy)O2 materials (y = 0, 0.01, 0.03, 0.05, 0.07 and 0.10). Overall the increase in doping up to …
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It's Not a SKZCAM! Accurate Surface Chemistry at Low Cost
… quantities like the adsorption energy and oxygen vacancy formation energy to be calculated. Consistently achieving accurate predictions will require going beyond the standard density functional theory (DFT) to methods like coupled cluster theory with single, double, and perturbative triple …
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Pyrochlore spin ice Dy2Ti2O7: Investigating a platform for magnetic monopolar quasiparticles
… of monopole quasiparticles: competing effects of oxygen vacancy defect sites in bulk crystal, and effects of strains and surfaces in real spin ice systems. Investigation of these issues began with collaborating on the growth of Dy2Ti2O7 crystals in a range of oxygen environments, and of Dy2Ti2O7 …
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Materials, Device, and System Integration of Amorphous Oxide Semiconductor TFTs
… to suppress the instability originating from the oxygen vacancy. The silicon-oxygen bond has a higher dissociation energy, which improves retention of oxygen atoms in the film, and thus, increases the transistor’s stability. This detailed study follows a bottom-up approach. It starts with the …
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Experimental investigations of oxygen-separating ion transport membranes for clean fuel synthesis
… the potential for 100% selective separation of oxygen from air. ITMs operate at extreme temperatures (>800°C), necessary for the mobility of lattice oxygen ions: this can result in significant experimental challenges. Specifically, the local gas compositions at both the high oxygen (air) and low …
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Activating oxygen chemistry on metal and metal oxides: design principles of electrochemical catalysts
… the next decades. However, the slow kinetics of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) lead to great energy loss in many electrochemical energy devices, including polymer electrolyte membrane fuel cells (PEMFCs), water splitting electrolyzers, and rechargeable …
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