Controlled growth and electrical characterization of bent single-walled carbon nanotubes

The frequency of appearance and curvature of zigzag shaped single-walled carbon nanotubes (SWNTs) are tailored by adjusting the gas flow rate, and changing the gas flow direction with respect to the step-edges on a single-crystal quartz substrate. The electrical resistance of SWNTs is found to increase with the number of bends. The resistance in SWNT segments with sharp curvature is observed to be 10-880 kOmega microm(-1) higher than that in segments with smooth curvature. The increment in resistance may be attributed to the introduction of topological defects and heterojunctions at the curved part. Our results suggest the possibility of growing SWNTs with multiple-bend geometry in a simple one-step process and modulating the conductance of SWNTs by controlling the number of bends and the curvature of bends.