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 20 for “"nanotube growth"”.
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Effects of catalyst pretreatment for carbon nanotube growth
… of pretreatment of iron catalyst for carbon nanotube (CNT) growth was studied. CNTs were grown on Fe/A1203 (1/10 nm) thin-film catalyst deposited on silicon substrates via exposure to C2H4 in a thermal chemical vapor deposition (CVD) furnace. During CVD, the sample was exposed to a carrier …
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Chemical, mechanical, and thermal control of substrate-bound carbon nanotube growth
Carbon nanotubes (CNTs) are long molecules having exceptional properties, including several times the strength of steel piano wire at one fourth the density, at least five times the thermal conductivity of pure copper, and high electrical conductivity and current-carrying capacity. This thesis …
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Carbon nanotube growth on challenging substrates : applications for carbon-fiber composites
… coated with radially-aligned arrays of carbon nanotubes (CNTs), which can enable through-thickness and interply matrix reinforcement of carbon-fiber-reinforced composites while simultaneously providing additional multifunctional benefits such as electrical and thermal conductivity enhancement. …
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Modeling and control of a silicon substrate heater for carbon nanotube growth experiments
… research group at MIT is working on carbon nanotube growth experiments on silicon substrates and in microfabricated silicon devices, to try to produce improved bulk nanotube growth. For this thesis, a heating control system was designed and implemented for eventual use in CNT growth …
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Engineering carbon nanostructures : development of novel aerogel-nanotube composites and optimization techniques for nanotube growth
… for evaluating 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 …
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Methodology, morphology, and optimization of carbon nanotube growth for improved energy storage in a double layer capacitor
The goal of this thesis is to optimize the growth of carbon nanotubes (CNTs) on a conducting substrate for use as an electrode to improve energy density in a double-layer capacitor. The focus has been on several areas, such as substrate material, growth conditions, catalyst variations, and …
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Bringing down barriers to the tunability, purity, and scalability of imogolite nanotubes
Synthetic imogolite is an aluminosilicate nanotube 2.1 to 2.3 nm wide and up to 1000 nm long. The high aspect ratio and ability to modify specific functional groups are desirable attributes affording it a wide range of potential. Additionally, the isomorphic substitution of Ge for Si in the …
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Synthesis and electrical property measurements of individual layered transition metal dichalcogenide nanotubes and nanowires
Nanotubes of the layered transition metal dichalcogenides (LTMDs) including MoS2, WS2, ReS2, and ReSe 2 have been synthesized. Additionally, nanowires of WS2 have been synthesized. All of the 1-dimensional structures synthesized used some form of a template to structurally direct 1-dimensional …
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Computational Study of Carbon-Based Low-Dimensional Materials on Structures, Properties and Applications
… model- jellium model- has been applied in carbon nanotube growth. The termination effect and the chiral selectivity in CNT growth have been investigated.
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Carbon nanotube applications for CMOS back-end processing
Carbon nanotubes are a recently discovered material with excellent mechanical, thermal, and electronic properties. In particular, they are potential ballistic transporters and are theorized to have thermal conductivities greater than any other material currently known. In this thesis, we will …
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High energy and power density nanotube-enhanced ultracapacitor design, modeling, testing, and predicted performance
… stored. This thesis presents vertical carbon nanotubes-based electrodes designed to achieve, when packaged into an ultracapacitor cell, a four to seven times higher power density (7.8 kW/1) and a five times higher energy density (31 Wh/1) than those of activated carbon-based ultracapacitors. …
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On the mechanism of carbon nanotube formation by means of catalytic chemical vapour deposition
… enormous strides in the synthesis of carbon nanotubes (CNTs), the mechanism for growth is still a highly debated issue. It is generally accepted that the model for carbon filament growth [1, 2], derived from concepts of vapour-liquid-solid theory, also applies to CNT growth. However, this …
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Block copolymer-templated iron oxide nanoparticles for bimodal growth of multi-walled carbon nanotubes
Since their discovery carbon nanotubes (CNTs) have sparked great interest due to their exceptional mechanical, electrical, and thermal properties. These properties make carbon nanotubes desirable for numerous applications including: nanoelectronics, high-strength composites, energy storage, …
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Flame synthesis of carbon nanotubes and metallic nanomaterials
Carbon nanotubes are a remarkable material with many appealing properties. Despite the appeal of this material, there are few synthesis techniques capable of producing nanotubes in large quantities at low-cost. The broad objective of this study was to examine the potential of a premixed flame for …
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Origami-inspired nanofabrication utilizing physical and magnetic properties of in situ grown carbon nanotubes
Carbon nanotubes (CNTs), in particular the vertically-aligned variety grown through a plasma enhanced chemical vapor deposition (PECVD)-based process, are highly versatile nanostructures that can be used in a variety of nanomanufacturing applications. However, process and material compatibility …
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Mechanical and Thermal Characterization of Continuous Fiber-Reinforced Pyrolysis-Derived Carbon-Matrix Composites
… in which the pyrolysis promoted in-situ carbon nanotube growth to form “fuzzy fibers”. The carbon phenolic composites were pyrolyzed to produce carbon-carbon composites. Several types of composites are examined and compared, including conventional phenolic and carbon-matrix composites. Through …
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Molecular Simulation Of Nanoscale Transport Phenomena
… reports simulations of (1) ion intake by carbon nanotubes, (2) hydrogen storage in carbon nanotubes, (3) carbon nanotube growth and (4) nanoscale heat transfer. Ion transport is investigated in the context of desalination of a polar solution using charged carbon nanotubes. Simulations demonstrate …
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A study of carbon based materials for energy applications
… and low temperature process. It facilitates the growth of CNTs and graphene on particular sites of the substrate. The objective of this research project was to study the growth of CNTs and graphene using PECVD system and to employ them in renewable energy devices. Excimer laser processed …
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Approaches for alignment and purification of single walled carbon nanotube thin films and their application in device electronics
… arrays of semiconducting single walled carbon nanotubes (SWNTs) represent one of the most promising materials for low cost, high performance electronic today. Over the years, a great deal of progress has been made towards this goal, however, to date, there are still key challenges associated …
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Study of phenomenologies during templated solid-state dewetting of thin single crystal films
… fuel cells, and catalysts for nanowire and nanotube growth. Solid-state dewetting of single crystal films leads to a very regular morphology, due to anisotropy in surface energy and surface self-diffusivity. When such films are templated by pre patterning, regular dewetting patterns, much …