Sub-5-nm gaps prepared by on-wire lithography: Correlating gap size with electrical transport

An on-wire lithography (OWL)-based method is developed to produce gap structures on the sub-5-nm length scale. The method utilizes nanowires with sacrificial layers incorporated along the long axis of the wire, which are coated on one face with silica. The advantages of OWL for nanoelectrodes include the ability to fabricate sub-20-nm gaps in high yield, precise dimensional control, and high batch-to-batch reproducibility. Au wires has been synthesized with Ni stripes through the template synthesis method using an anodic aluminum oxide (AAO) template and literature procedures to evaluate the range of gaps that can be fabricated by OWL. The method is simple and easily adoptable and can be ideally suited to fabricate structures, which can be used to make measurements on nanomaterials and individual molecules.