Vapor transport techniques for growing macroscopically uniform zinc oxide nanowires


Vapor transport techniques for growing macroscopically uniform zinc oxide nanowires

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dc.contributor.advisor Hall, Matthew John
dc.creator Baker, Chad Allan 2010-06-04T14:48:50Z 2010-06-04T14:48:50Z 2009-08 2010-06-04T14:48:50Z August 2009
dc.description.abstract ZnO nanowires were grown using carbothermal reduction and convective vapor phase transport in a tube furnace. Si <100> substrates that were 20 mm x 76.2 mm were sputter coated with 2 nm to 50 nm gold which formed nanoparticles on the order of 50 nm in diameter through a process of Ostwald ripening upon being heated. Growth temperatures were varied from 800ºC to 1000ºC, flow rates were varied from 24 sccm to 3300 sccm, and growth durations were varied from 8 minutes to 5 hours. Vapor phase Zn, CO, and CO2, produced by carbothermal reduction and suspended in an Ar atmosphere, were flowed over the Si substrates. The Au nanoparticles formed an eutectic alloy with Zn, causing them to become liquid nanodroplets which catalyzed vapor-liquid-solid nanowire growth. The nanowires were also synthesized by self-catalyzing vapor-solid growth in some cases. Using the tube furnace never resulted in more than 50% of the substrate being covered by nanowires. It was found that a bench-top furnace could achieve nearly 100% nanowire coverage by placing the 20 mm x 76.2 mm sample face down in a quartz boat less than 2 mm above the source powder. This was because minimizing the distance between the sample and the source powder was critical to achieve macroscopically uniform growth consistently.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subject nanowires
dc.subject nano-wires
dc.subject catalyst
dc.subject catalytic
dc.subject vapor-liquid-solid
dc.subject vapor liquid solid
dc.subject vapor-solid
dc.subject vapor solid
dc.subject vapor-solid-solid
dc.subject vapor solid solid
dc.subject carbothermal
dc.subject ZnO
dc.subject zinc oxide
dc.subject nanocombs
dc.subject nano
dc.subject rugosity
dc.subject vapor transport
dc.subject vapor phase transport
dc.title Vapor transport techniques for growing macroscopically uniform zinc oxide nanowires
dc.contributor.committeeMember Shi, Li, Ph. D.
dc.description.department Mechanical Engineering
dc.type.genre thesis
dc.type.material text Mechanical Engineering Mechanical Engineering The University of Texas at Austin Masters Master of Science in Engineering

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