Controllable nanogap fabrication on microchip by chronopotentiometry

This work aims to solve one of the key issues for developing molecular and nanoscale devices, i.e., how to controllably fabricate nano/angstrom-size gaps on microchips. It has been shown that with a galvanostat and use of the electrode potential as the feedback, we can be used to electrochemically fabricate metallic electrode pair with controlled gap widths ranging from about ten nanometers down to few angstroms. It is based on probing the potential drop in the electrical double layer across the two electrodes during the narrowing of the gap. The process is simple and controllable, allowing rapid fabrication of nanogaps and adaptation of a commonly used electrochemical instrument.