Large-scale directed assembly of single-walled carbon nanotube devices by alternating current coupling dielectrophoresis

Abstract

Single-walled carbon nanotubes (SWNTs), especially suspended SWNTs, have attracted the attention of many researchers due to their unique properties. However, the processes to maintain suspended SWNTs in a controllable individual or single bundle deposition cannot be scaled up in conventional carbon nanotube device fabrication. In this study, we demonstrate the assembly of suspended SWNTs with controllable bridging through alternating current (AC) coupling dielectrophoresis (DEP). We also analyze the mechanism underlying the incisive change in dielectrophoretic force fields when a single SWNT bundle has assembled onto a contact position, leading to a reproducible directed assembly that is self-limiting in forming single SWNT bundle devices. One of the main controllable bridging condition of a suspended SWNT bundle is generated by the variation of the electric-field distribution around the electrode pair. This is verified by electric-field simulation of pre- and post-deposition of an individual SWNT.