Fabrication of stable metallic nanowires with quantized conductance

A metallic nanowire with quantized conductance was fabricated by electrochemically etching a narrow portion of a metallic wire supported on a solid substrate down to the atomic scale. The width of the nanowire was controlled flexibly by etching atoms away or depositing atoms back onto the wire with the electrochemical potential. Using a feedback loop this method can, at will, fabricate a single or an array of long-term stable nanowires with a pre-selected quantized conductance. These stable nanowires may be used in devices as digitized conductors and as sensors that detect chemicals in the air or in solutions. Using the conductance quantization as a feedback, this method may be used to fabricate nanoelectrodes by etching off the last few atoms in the thinnest portion of each nanowire. These nanoelectrodes may be connected to single molecules in molecular devices.