Title:
LCVD synthesis of carbon nanotubes and their characterization

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dc.contributor.advisor Lackey, W. Jack
dc.contributor.author Bondi, Scott Nicholas en_US
dc.contributor.committeeMember Mostafa Ghiaasiaan
dc.contributor.committeeMember Melkote, Shreyes N.
dc.contributor.committeeMember Thomas Starr
dc.contributor.committeeMember Z. L. Wang
dc.contributor.department Mechanical Engineering en_US
dc.date.accessioned 2005-03-01T19:21:40Z
dc.date.available 2005-03-01T19:21:40Z
dc.date.issued 2004-08-12 en_US
dc.description.abstract The primary goal of this research was to develop the laser chemical vapor deposition (LCVD) process to be able to directly deposit carbon nanotubes onto substrates selectively. LCVD has traditionally been used to directly deposit complex geometries of other materials, including many metals and ceramics. Carbon nanotube deposits were formed using codeposition and other techniques. Multiwall carbon nanotubes as small as 7 nm were synthesized. Utilizing electron microscopy, deposits were characterized to determine the effects of laser power, catalyst and hydrocarbon concentration, time, pressure, and other variables on the number of nanotubes formed, their size, and their spatial location. The most important variables were shown to be hydrocarbon and catalyst concentration and laser power. These results were analyzed and statistics based models were developed to express these trends. Additionally, the process was also used successfully to deposit linear patterns of carbon nanotubes. Carbon nanotube deposits were also carried out in the presence of an electric field. It was demonstrated that a field of sufficient strength could be used to orient tube growth. LCVD is a thermally driven process and a thermal feedback and control system is typically employed to allow for real time control of the reaction zone temperatures. The current thermal imaging system installed on the LCVD reactor is limited to operation at temperatures above which nanotube deposition occurs. A heat and mass transport model was therefore developed to simulate deposition temperatures and provide an estimate of the desired laser power needed to achieve a desired reaction temperature. This model included all significant modes of heat transport including conduction, natural convection and radiation. Temperature dependant material properties were also employed to help achieve greater accuracy. Additionally, the model was designed to be able to simulate a scanning laser beam which was used to deposit linear patterns of carbon nanotubes. Modeling calculations of laser heating compared favorably with experimental data. The results of this work show that LCVD has potential for use in the commercial market for selective direct deposition of patterns of aligned carbon nanotubes on multiple substrate materials. en_US
dc.description.degree Ph.D. en_US
dc.format.extent 105926700 bytes
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/4780
dc.language.iso en_US
dc.publisher Georgia Institute of Technology en_US
dc.subject Carbon nanotubes en_US
dc.subject Laser chemical vapor deposition
dc.subject Nanotube synthesis
dc.subject LCVD
dc.subject Laser heating
dc.subject Thermal modeling
dc.title LCVD synthesis of carbon nanotubes and their characterization en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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