Vapor transport techniques for growing macroscopically uniform zinc oxide nanowires
MetadataShow full item record
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.
Showing items related by title, author, creator and subject.
Multi-nozzle molecular beam apparatus and experiments/theory of vapor-phase mixing in amorphous solid water Barlow, Evan Tolman, 1980- (2007-05)Herein are contained a design of a multi-nozzle vapor deposition molecular beam apparatus for ultra-high vacuum applications, experimental results and conclusions regarding surface templating of crystallization in amorphous ...
Harrison, Shay; Crocker, James E.; Manzur, Tariq; Marcus, Harris L. (1996)Gas phase solid freeform fabrication research at The University of Connecticut focuses on two main procedures, Selective Area Laser Deposition (SALD) and Selective Area Laser Deposition Vapor Infiltration (SALDVI). A SFF ...
Zong, G.S.; Carnes, R.; Wheat, H.G.; Marcus, H.L. (1990)Laser chemical vapor deposition is capable of selective area deposition of thin fums at high spatial resolution, and in the present work this advantage was used to perform solid freeform fabrication (SFF). The pyrolytic ...