Controlled fabrication of electrodes with a few nanometer spacing by selective etching of a GaAs/AlGaAs heterostructure

We present a nanofabrication technique to make electrodes with a separation below 10 nm. This technique takes advantage of the atomic precision of molecular beam epitaxial growth. The key step in the fabrication is the formation of a nanotemplate by selective etching on the cleaved surface of a GaAs/AlGaAs heterostructure. Electrodes with a spacing less than 10 nm are formed by angle evaporation of Au on such a template. The technique can also be extended to fabricate three electrodes that are all less than 10 nm from each other.