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 22 for “"Direct growth"”.
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Direct Growth of Carbon Nanotubes on Inconel Sheets Using Hot Filament Chemical Vapor Deposition
… issues limiting their applications, namely: (1) direct growth of CNTs without additional catalyst, (2) secondary growth of carbon nanotubes on primary CNT bed without using extra catalyst, (3) and CNT alignment mechanisms during the growth. The CNTs used in this thesis were prepared by hot …
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Dislocation engineering in InAlGaAs/SiGe alloy systems for heteroepitaxial integration
… is receiving widespread adoption involves the direct growth of Ge on Si. It produces a threading dislocation density ~2x10⁷ cm⁻² but this density is too high for applications like high efficiency GaAs solar cells.
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Synthesis and Characterization of Complex Polymer Topologies using Ring-Opening Metathesis Polymerization
… synthesis of bottlebrush polymers using a direct-growth approach results in a controlled product and monomodal size exclusion chromatography (SEC) peaks. The optimization of the direct-growth approach depends on two factors: monomer type and percentage of monomer to polymer conversion in …
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Engineering carbon nanostructures : development of novel aerogel-nanotube composites and optimization techniques for nanotube growth
… a metal's ability to catalyze nanotube growth, including in situ carbothermic reduction of oxidized nanoparticles to their catalytic metallic phase as they form and production of a bulk quantity of nanoparticles which can be easily characterized. In this work, metal-doped carbon aerogels …
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Mesoporous ZnO/TiO2 nanowire heterojunction photo-anodes for quantum-dot sensitised solar cells
… due to their superior electron mobility and direct growth capabilities. Their one-dimensional nanostructure provides a direct pathway for electron transport, significantly reducing recombination losses and enhancing charge collection efficiency. ZnO NWs may be grown at lower temperatures and …
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Design of III-V Multijunction Solar Cells on Silicon Substrate
… but are also more expensive than Si substrate. Direct integration of high efficiency III-V solar cells on larger diameter, cheaper and readily available Si substrate is highly desirable for increased density, low-cost and lightweight photovoltaics. However, the polar-on-nonpolar epitaxy, the …
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The impact of remittances on financial sector development: An exploration in the SADC region
… given the extensive literature documenting the direct growth enhancing effect of financial development, and consequently, poverty reduction. In particular, annual data from 11 countries in the South African Development Community (SADC) are analysed from 1990 to 2011 using the panel data analysis …
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Integration of III-V optical devices and interconnects on Si using SiGe virtual substrates
… epitaxy, and thermal mismatch make the direct growth of high quality GaAs-based material on Si difficult. However, with the use of SiGe virtual substrates, Si substrates that have the Ge lattice constant, this goal can be achieved since Ge and GaAs have a small lattice mismatch of only …
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Synthesis and characterization of electronic materials for photovoltaic applications
… bulk heterojunction materials via a seeded growth process. Electropolymerizable Schiff base complexes have been designed, synthesized, and utilized as precursors for conducting metallopolymers. The embedded metal centers are used as seed points for direct growth of size-controllable …
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Heterostructures Prepared by Surface Modification of Nanocrystals
… formation of metal oxide-Au heterostructures by direct growth of Au NCs. Based on studies of surface cap exchange reaction of single component NCs, Au-Fe3O4 heterodimers have been asymmetrically surface modified to utilize coalescence of small Au particles to bring together different types of …
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Advanced Electrochemical Analysis for Complex Electrode Applications
… examples. Chapter 5 demonstrates the direct growth of vertically aligned CNT forests on a gold electrode. The electrochemical response of the fabricated electrode has also been examined with ferrocyanide as the redox species. Furthermore, the immobilisation of anthraquinone onto CNT …
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III-V compositionally graded buffers for heterostructure integration
… devices on Si substrates also used the direct growth of Ge on Si offcut substrates. InAsxP₁-x compositionally graded buffers were investigated for the growth of InyGa₁-yAs compositions with lattice constants greater than InP. We report the effects of strain gradient, growth temperature, …
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Monolithic integration of 1.55 micron photodetectors with GaAs electronics for high speed optical communications
… high speed GaAs electronics, which requires the direct growth of InGaAs on lattice-mismatched GaAs substrates using molecular beam epitaxy (MBE). A customized OEIC chip was designed and fabricated. Lattice-mismatched MBE growth was studied and InGaAs photodetectors on GaAs were produced using the …
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Development of REBCO Tapes on Non-Metallic Flexible Substrates for RF Applications
… superconductors (2G-HTS) are well developed for direct current (DC) applications. However, alternating current (AC) losses because of eddy currents in Hastelloy dominate at microwave frequencies. This work aims to develop REBCO on inexpensive and non-metallic flexible substrates for RF …
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Heterogeneous Integration of III-V Multijunction Solar Cells on Si Substrate: Cell Design and Modeling, Epitaxial Growth and Fabrication
… mismatch polar-on-nonpolar epitaxy makes the direct growth of GaAs on Si challenging, rendering the metamorphic cell sensitive to dislocations. The focus of this dissertation is to systematically investigate heterogeneously integrated III-V multijunction solar cells on Si substrate. Utilizing …
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Diamond seeding process for the heterogenous integration of high quality diamond on semiconductors
… to improve seeding density, nucleation process, growth kinetics, film morphology, quality as well as material thermal properties of diamond film on different semiconductors. The growth of high-quality diamond on silicon as well as III-Nitrides were achieved through a series of experiments and …
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Heteroepitaxial Germanium-on-Silicon Thin-Films for Electronic and Photovoltaic Applications
… mismatch, polar on non-polar epitaxy makes the direct growth of GaAs on Si challenging, rendering the metamorphic cell sensitive to dislocations. The focus of this dissertation is to investigate heterogeneously integrated 1J GaAs solar cells on Si substrate using germanium (Ge) as an …
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Wettability of graphitic materials and their application in separation
… a scalable chemical vapor deposition method by direct growth of the CNT on a nickel alloy (Hastelloy) mesh with micrometer-sized openings. The developed membrane is superhydrophobic, corrosion and oxidation resistant (up to 500 °C), and shows similar desalination performance as a commercial …
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Multi-scale electrical and thermal properties of aligned multi-walled carbon nanotubes and their composites
… fibers, and polymer) was fabricated through direct growth of radially aligned CNTs on 11 pm-diameter alumina fibers in a woven cloth and hand lay-up. Measured laminate electrical and thermal properties (-1 W/mK and -100 S/m) were consistent with the A-CNT-PNC study, and confirmed the …
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Tissue engineering of a tracheal substitute
… electron microscopy (SEM) was used to assess the growth and characterise the differentiation of human respiratory epithelial cells (REC) cultured on two biomaterial scaffolds. The first scaffold, based on a hyaluronic acid derivative, was observed to be non-adhesive for REC. This lack of adhesion …
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