Vertically aligned single-walled carbon nanotube growth by a hot filament chemical vapor deposition method

PRES 61

Ya-Qiong Xu, yqxu@rice.edu1, Erica Flor, Howard Schmidt, Richard Smalley, and Robert Hauge, Hauge@rice.edu2. (1) Carbon Nanotechnology Lab, Rice University, 6100 Main Street, MS100, Houston, TX 77005, (2) Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main Street, MS100, Houston, TX 77005
A hot filament chemical vapor deposition method (HFCVD) has been developed to grow vertically aligned single-walled carbon nanotubes (VA-SWNTs). Silicon substrates decorated with islands of iron were rapidly inserted into a preheated furnace in which a hot filament is activating the gas. VA-SWNTs are produced with diameters ranging from 0.78 to 1.6 nm. We find that rapid heating in the presence of atomic hydrogen and active carbon species such as ethylene and acetylene permits nucleation of SWNTs on catalyst particles before they are mobilized on the surface. Isotopic shifts of the tangential phonon mode of SWNTs indicate that SWNT growth occurs primarily via reactions of acetylene and ethylene. Finally the presence of atomic hydrogen appears to be essential for both nucleation and growth of VA-SWNTs in this HFCVD.