Methods to fabricate nanocontacts for electrical addressing of single molecules

Recently, nanotechnology has entered the fields of sensors and biosensors. Of particular interest is how sensitivity, selectivity, and switching may be improved by directly contacting single molecules. To achieve this goal, the fabrication of electrodes separated by nanometric size gaps that may be bridged by single molecules is necessary. Two approaches to fabricate nanometric sized contacts were recently proposed in literature. The first involves the movement of electrodes pairs. The second relates to the formation of electrodes pairs via etching. The aim of this work is to review techniques of fabricating nanometer scale gaps between conducting materials, used to form nanocontacts to single molecules.