Fabrication of nanoelectrodes based on controlled placement of carbon nanotubes using alternating-current electric field

Abstract

A fabrication process for nanoelectrodes with a nanogap of ∼35 nm is presented. This process is based on controlled placement of carbon nanotubes on metal electrodes using an alternating-current (ac) electric field. One bundle of single-walled nanotubes (SWNT) was placed successfully between two electrodes using an ac electric field. Electrical measurement of the SWNT bundle through the two metal contacts shows nonlinear current-voltage characteristics, similar to those of the two back-to-back Schottky diodes. The nanoelectrodes were fabricated using a single bundle of SWNTs as a shadow mask. The SWNT bundle was suspended on the metal electrodes on top of the photoresist supporter using the ac electric-field alignment. After evaporation of Al and liftoff, nanoelectrodes with a gap of ∼35 nm were successfully obtained. A simple model is proposed which suggests that gaps ranging from 10 to 50 nm can be fabricated through adjustment of the distance from the source to the substrate.