Abstract
In the past decade, there have been a lot of progress in the research of carbon materials. The discovery of fullerenes has given us a whole new insight into carbon materials. Furthermore, since the carbon nanotubes (CNTs) were discovered by Iijima in 1991, many potential applications have been proposed for carbon nanotubes, including electron transport, high-strength composites, energy storage, sensors, field emission displays, nanometer-sized semiconductor devices, probes, and drug release. Some of these applications have now been realized in commercial products. A great deal of effort has been devoted to the research of manufacture and properties of carbon nanotubes. In this study, CNT bundles were fabricated via pyrolysis of hydrocarbons by chemical vapor deposition. A template-synthesis method based on the porous anodic aluminum oxide membrane was applied. Both one-step and two-step processes were attempted to improve the morphologies of CNT bundles. The effect of amount of catalyst on fabricating the CNT bundles was studied as well. The bundles with 200-300nm in diameter and several micrometers in length were composed of amorphous carbon film on the outside and tangled muti-walled carbon nanotubes with an average outer diameter of 13nm inside the film. In addition, the mechanical properties of the CNT bundles fixed by platinum pads at both ends were studied by nanoindentation. The elastic modulus of a single CNT bundle was calculated to be 33 GPa. The field emission properties were also measured. It exhibited a turn-on field of 2.64 V/μm as the electric current density reached 10 μA/cm2 from the J-E curve. The field enhancement factor was calculated to be 891 from the F-N plot.