Nanometer-scale quantum channels defined by reactive ion etching in InAs/AlSb heterojunctions

An approach to the lateral confinement of electrons in an InAs quantum well has been developed. Conducting quantum wires, rings, and dots with lateral dimension ⩾50 nm have been fabricated by using electron-beam lithography and reactive ion etching. Due to the Fermi level pinning at InAs surface, the lateral confinement is abrupt and approximately square. Magnetotransport characterization on a series of fabricated hallbars demonstrate that, despite damage by energetic ions, the electron transport in these quantum wires is in the quasiballistic regime at 4.2 K.