Controlled fabrication of nanogaps in ambient environment for molecular electronics

Abstract

We have developed a controlled and highly reproducible method of making\nnanometer-spaced electrodes using electromigration in ambient lab conditions.\nThis advance will make feasible single molecule measurements of macromolecules\nwith tertiary and quaternary structures that do not survive the liquid-helium\ntemperatures at which electromigration is typically performed. A second advance\nis that it yields gaps of desired tunnelling resistance, as opposed to the\nrandom formation at liquid-helium temperatures. Nanogap formation occurs\nthrough three regimes: First it evolves through a bulk-neck regime where\nelectromigration is triggered at constant temperature, then to a few-atom\nregime characterized by conductance quantum plateaus and jumps, and finally to\na tunnelling regime across the nanogap once the conductance falls below the\nconductance quantum.\n