Single-walled carbon nanotubes: Growth, device fabrication and device applications

The effect of gas environment on the electronic properties of carbon nanotubes has recently attracted certain attention. Gas adsorption in carbon nanotubes is an important issue for both fundamental research and technical application of nanotubes.;In this thesis contacts are made to individual single-walled carbon nanotubes with gold/titanium and adsorption/desorption properties are studied. The adsorption/desorption measurements showed a two order of magnitude increase in the resistance of SWNT device following the degassing of the sample. The response of individual SWNTs to the exposure of O2 molecules is therefore more sensitive as compared to that of SWNT bundles and ropes. It was also observed that the SWNT device behaves as a p-type semiconductor when exposed to oxygen and n-type when the sample is degassed. Also the gate voltage (Vg) dependence of Ids shows that the threshold voltage for both the n-type and the p-type devices is the same, indicating that there is no charge transfer between the O2 molecule and the SWNT. (Abstract shortened by UMI.).