Date of Award
2007
Degree Type
Thesis
Degree Name
Master of Engineering Science
Program
Mechanical and Materials Engineering
Supervisor
Dr. Andy Sun
Abstract
Nanotechnology and nanomaterials have recently become a fast-growing area of research and engineering that are predicted to revolutionize many materials and technologies that we use in everyday life. Carbon nanotubes (CNTs), as one of the key elements in nanotechnology, are a class of new and one-dimensional nanomaterials with unique structures and properties for various potential applications from nanoelectronics to nanocomposite materials. The key challenge for the implementation of carbon nanotubes into advanced technologies is the control of their synthesis, properties and morphologies. There are several synthesis methods that can be used to control the growth of carbon nanotubes, but the best method is chemical vapour deposition (CVD). The CVD method allows for the growth of bulk quantities of nanotubes and is scalable to industrial levels, while facilitating the control of the morphology and orientation of the nanotubes. The CVD method is also very flexible, and allows a variety of chemical reagents and experimental parameters to be used. The objective of this thesis work is to explore CVD methods, including speciallydesigned Ohmically-heating CVD and floating catalyst CVD, to synthesize high density nanotubes on silicon and carbon paper substrates. The emphasis was put on optimizing various experimental parameters such as hydrocarbon sources (gas, liquid and solid), temperature and growth time in order to control the quality and structure of carbon nanotubes. The effects of sulfur addition on the growth and structure were investigated. The doping of nitrogen into carbon nanotubes was also studied to enhance electrical and mechanical properties. Various characterization techniques such as scanning electron microscopy (SEM), field-emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution TEM were used to examine the structure and morphology of resultant nanotubes. Detailed growth mechanisms will also be proposed. It is anticipated that the nanotubes grown with a high degree of vertical alignment on flat silicon substrates can find potential applications chemical and biological sensor technologies, and nanotubes grown in high densities on carbon paper substrates provide a very high surface area for the support of platinum particles for use in hydrogen fuel cell electrodes.
Recommended Citation
Arato, David, "Controlled Synthesis of Carbon Nanotubes by Chemical Vapor Deposition on Silicon and Carbon Substrates" (2007). Digitized Theses. 5017.
https://ir.lib.uwo.ca/digitizedtheses/5017