Controlled growth and electrical characterization of bent single-walled carbon nanotubes
J. Huang, W.B. Choi
Florida International University, US
Keywords: bent SWNT
Abstract:The unique electrical and mechanical properties of single-walled carbon nanotubes (SWNTs) make them one of the most promising candidates for next generation nanoelectronics. However, synthesis of complex geometries for as-grown SWNTs still remains a challenging task. To integrate SWNTs into nanoelectronic circuit or nanoelectromechanical systems (NEMS), it is necessary to grow SWNTs having different morphologies and functionalities. Very recently, SWNTs with multiple bends have been grown by catalytic chemical vapor deposition using Fe/Mo bimetallic catalyst encapsulated on alumina nanoparticles. The frequency of appearance and curvature of bent 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 single-crystal quartz substrate. Electrical resistance of SWNTs is found to increase with number of bends. The resistance in SWNT segments with sharp curvature is observed to be 10 - 880 k/µm higher than that with smooth curvature. The increment in resistance may be attributed to the introduction of topological defects and hetero-junctions at the curved part. Our results suggest the possibility of growing SWNTs with multiple bend geometry in a simple one-step process and modulating conductance of SWNTs by controlling the number of bends and the curvature of bends. A wide range of potential applications can be suggested for the utilization of the bent SWNTs, such as heating and cooling elements, MEMS/NEMS components and pressure sensors.