Fabrication of metallic electrodes with nanometer separation by electromigration

A simple yet highly reproducible method to fabricate metallic electrodes wi th nanometer separation is presented. The fabrication is achieved by passin g a large electrical current through a gold nanowire defined by electron-be am lithography and shadow evaporation. The current flow causes the electrom igration of gold atoms and the eventual breakage of the nanowire. The break ing process yields two stable metallic electrodes separated by similar to 1 nm with high efficiency. These electrodes are ideally suited for electron- transport studies of chemically synthesized nanostructures, and their utili ty is demonstrated here by fabricating single-electron transistors based on colloidal cadmium selenide nanocrystals. (C) 1999 American Institute of Ph ysics. [S0003-6951(99)03427-0].