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

A fabrication process for nanoelectrodes with a nanogap of similar to35 run 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 similar to35 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. (C) 2004 American Vacuum Society.