We have developed a controlled and highly reproducible method of making nanometer-spaced electrodes using electromigration in ambient lab conditions. This advance will make feasible single molecule measurements of macromolecules with tertiary and quaternary structures that do not survive the liquid-helium temperatures at which electromigration is typically performed. A second advance is that it yields gaps of desired tunnelling resistance, as opposed to the random formation at liquid-helium temperatures. Nanogap formation occurs through three regimes: First it evolves through a bulk-neck regime where electromigration is triggered at constant temperature, then to a few-atom regime characterized by conductance quantum plateaus and jumps, and finally to a tunnelling regime across the nanogap once the conductance falls below the conductance quantum.
@article{arxiv.cond-mat/0504112,
title = {Controlled Fabrication of Nanogaps in Ambient Environment for Molecular Electronics},
author = {D. R. Strachan and D. E. Smith and D. E. Johnston and T. -H. Park and M. J. Therien and D. A. Bonnell and A. T. Johnson},
journal= {arXiv preprint arXiv:cond-mat/0504112},
year = {2009}
}