Tip-to-tip growth of aligned single-walled carbon nanotubes under an electric field

An electric field was applied during the chemical vapor deposition process for fabricating directional single-walled carbon nanotubes (SWNTs). The electric field significantly affected the direction of the carbon nanotubes (CNTs) synthesized on multi-layered substrate. Acetylene and hydrogen were used as carbon precursor and reducing gas, respectively. Thin Ni and Fe films were used as catalysts for CNT growth. The Ni film with a thickness ranging from 1 to 10 nm was coated oil Cr layer, which was patterned on SiO2/Si substrate. The Cr layer, acting as an electrode, was etched to form a tip-to-tip pattern. The sharp edge of Cr electrode yields an enhanced electric field, which promotes the growth of SWNTs between the two tips. A theoretical analysis was proposed to model the electric field in the process, and the simulated electric field is quite consistent with the SWNT growth region around the tips. (c) 2006 Elsevier B.V. All rights reserved.