A novel InAs quantum wire system

We report here a new technique in patterning high quality low-dimensional electrons in single InAs quantum wells. Grown by molecular beam epitaxy, the single InAs quantum well is sandwiched between AlSb barriers and capped by a thin layer of InAs. When the InAs cap layer is patterned by electron beam lithography and selectively removed, electrons are induced in the InAs quantum well below due to the different surface Fermi level pinning voltages on the exposed AlSb layer from the InAs cap. One-dimensional quantum wires can thus be conveniently defined by lithography and nm-shallow etching. We demonstrate that these one-dimensional electrons posses a long elastic mean free path ( > 1.4 mum) and a long coherence length (> 3 mum) at 2 K. (C)) 2002 Elsevier Science B.V. All rights reserved.