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 20 of 68 for “"Heterojunctions"”.
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Silicon-germanium nanowire heterojunctions: Optical and electrical properties
… functional structures is the nanowire axial heterojunctions, especially lattice mismatched heterojunctions. Si and Ge have a considerable lattice mismatch of ~ 4.2% as well as a mismatch in the coefficient of thermal expansion, and the formation of a Si_{1-x}Ge_x transition layer at the …
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Epitaxial Gallium Oxide Heterojunctions for Vertical Power Rectifiers
At the heart of all power electronic systems lies the semiconductor, responsible for passing large amounts of current at negligible power losses in the on-state, while instantaneously switching to withstand high voltages in the off-state. For decades silicon (Si) has dominated nearly all aspects of …
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VISIBLE-LIGHT-ACTIVE SEMICONDUCTOR HETEROJUNCTIONS FOR ENHANCED PHOTOCATALYTIC ACTIVITY
A clean and sustainable energy source is a basic requirement for addressing the current increase in global energy demand and environmental issues. Because of its potential for solving current energy and environmental problems, semiconductor-based photocatalysis has received tremendous attention in …
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Modeling and Simulation of Electron Transport through Nanoscale Heterojunctions
… discusses some transport aspects of nanoscale heterojunctions, the archetypal devices which constitute a considerable part of the rapidly growing nanotechnology and nanoscience today. It discusses two distinct types of nanoscale heterojunctions, namely weakly correlated and strongly correlated …
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Internal Photoemission and Energy Band Discontinuities at Semiconductor Heterojunctions
… ($\Delta$E$\sb{\rm c})$ at certain semiconductor heterojunctions. The technique involves measuring the spectral response of specially designed p$\sp{+}$N$\sp{-}$ heterojunction photodiodes. Internal photoemission from the valence band of the p$\sp{+}$ layer is observed in these devices and power …
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Study of electrically active ceramic interfaces : ZnO based homojunctions and heterojunctions
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994.
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Development of spintronics devices and Type 1 heterojunctions from graphene nanoribbon superlattices
… on the superlattice topology, we can form Type 1 heterojunctions and materials with applications in spintronics. These results were used in conjunction with a nearest-neighbor tight-binding approach to differentiate between three structures formed from graphene nanoribbon superlattices with …
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Nanoscale heterojunctions of transition metal oxide and silicon for high-efficiency oxygen evolution reaction
… pursue the second approach and examine nanoscale heterojunctions of earth abundant materials. In this thesis, we employ density functional theory (DFT) calculations to investigate nanoscale heterojunctions of transition metal oxide and silicon (Si), which are commonly used for …
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Acoustic Phonon Scattering in Modulation Doped Aluminum(x) Gallium(1-X) Arsenide/gallium Arsenide Heterojunctions
… x}$Ga$\sb{1-\rm x}$As/GaAs modulation doped heterojunctions. We review previous measurements of the deformation potential constant Z and discuss the controversy over the discrepancy between the measured value of Z in bulk GaAs and in the heterojunction. By comparing the theory of scattering …
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Low temperature photoluminescence studies on sputter deposited cadmium sulphide/cadmium telluride heterojunctions and solar cells
Device quality CdS/CdTe heterostructures and completed solar cells (~12% efficient) have been studied using low-temperature photoluminescence (PL). The PL was studied as a function of temperature (82-295 K) and laser excitation power (0.02-2 mW). The CdS/CdTe junctions were grown on transparent …
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Semiconductor electronic band alignment at heterojunctions of wurtzite aluminum nitride, gallium nitride, and indium nitride
… thesis the band alignments for wurtzite (0001) heterojunctions of AlN, GaN, and InN semiconductors are measured by x-ray photoemission spectroscopy. The bands alignments are all found to be Type I, and the valence-band discontinuities are found to be:(UNFORMATTED TABLE OR EQUATION …
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First principles modelling of tunnel field-effect transistors based on heterojunctions of strained Germanium/InGaAs alloys
The limitations of the down-scaling of the silicon metal–oxide–semiconductor (MOS) field-effect transistor (FET) and the demand for energy-efficient appliances motivate the study of alternative devices. The device under consideration is the biaxial tensile-strained Germanium on InGaAs alloy tunnel …
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Demystifying metal-assisted chemical etching of III-N materials and multi-heterojunctions: fundamentals to optoelectronic applications
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01
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Energy Level Alignment in Hybrid Bulk Heterojunctions and New Redox Mediators for Quantum Dot Solar Cells
The advancement of quantum dot sensitized solar cell (QDSSC) technology depends on optimizing directional charge transfer between light absorbing quantum dots, TiO2, and a redox mediator. Kinetically, reduction of oxidized quantum dots by the redox mediator should be rapid and faster than the back …
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Interband quantum tunneling at the band-edges in III-V semiconductor heterojunctions for low-power logic and detectors
… explores interband tunneling in semiconductor heterojunctions where a density-of-states switching mechanism can be used to sharply modulate the junction conductance using small applied voltages via alignment and misalignment of the band-edges. Such a mechanism is useful for the pursuit of …
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Exploring and exploiting charge-carrier confinement in semiconductor nanostructures : heterodimensionality in sub-monolayer InAs in GaAs and photoelectrolysis using type-II heterojunctions
In this thesis, semiconductor nanostructures are studied, both experimentally and theoretically, to help aid the development of two diverse and important technologies. Firstly, charge-carrier confinement in stacked sub-monolayer (SML) InAs in GaAs: SML deposition results in the formation of In-rich …
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Composition, structure, and performance of nanocrystal bulk heterojunction photovoltaics
… Device efficiency was maximized for bulk heterojunctions employing the smallest titania nanocrystals, an indication that at constant volume fractions, larger titania nanocrystals decrease the total number of titania particles available to form complete and continuous pathways through the …
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Desenvolvimento de heterojunções constituídas de ZnO/g-C3N4 e ZnFe2O4/g-C3N4 para fotodegradação de contaminantes orgânicos emergentes
… treat such compounds. In this work, different heterojunctions of ZnO/g-C3N4 and ZnFe2O4/g-C3N4 in different mass proportions of g-C3N4 (10, 50, and 80 %) were synthesized through a simple method of mixing, sonication and heat treatment. The influence of the amount of g-C3N4 in the …
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Green Organic Solar Cells from a Water Soluble Polymer and Nancrystalline TiO2
… cells with various structures including bilayer heterojunctions, bulk heterojunctions and a hybrid of bilayer and bulk heterojunctions have been developed and explored. These results are comparable to the best polymer/metal-oxide solar cells reported by other groups using organic solvents.In …
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