Fabrication technique for nanometer-scale InAs quantum devices: Observation of quantum interference in Aharonov–Bohm rings and Coulomb blockade in quantum dots

Abstract

We report an approach to the lateral confinement of electrons in InAs/AlSb single quantum wells. Using electron-beam lithography and reactive ion etching, we have fabricated conducting wires, rings, and dots with lateral dimensions ⩾50 nm. Characterization on narrow wires and rings indicates that the electron transport is in the quasiballistic regime at 4.2 K. The current–voltage characteristics of 70-nm-diam dots in single-electron transistor structures show the Coulomb gap and the Coulomb staircase features. These artificially patterned devices have an ultimate lateral dimension of a few nanometers, limited by the resolution of electron-beam lithography.