Fabrication of metallic electrodes with nanometer separation by electromigration

A simple yet highly reproducible method to fabricate metallic electrodes with nanometer separation is presented. The fabrication is achieved by passing a large electrical current through a gold nanowire defined by electron-beam lithography and shadow evaporation. The current flow causes the electromigration of gold atoms and the eventual breakage of the nanowire. The breaking process yields two stable metallic electrodes separated by ∼1 nm with high efficiency. These electrodes are ideally suited for electron-transport studies of chemically synthesized nanostructures, and their utility is demonstrated here by fabricating single-electron transistors based on colloidal cadmium selenide nanocrystals.