Free-standing and overgrown InGaAs/GaAs nanotubes, nanohelices and their arrays

The possibility is shown to fabricate a wide class of free-standing nano-objects based on few monolayers thick scrolled heterostructures. Using an ultra-thin film (1 ML GaAs:1 ML InAs), nanotubes with an inside diameter of approximate to 2 nm have been obtained, which constitutes the limiting size for this system. Molecular-beam-expitaxy overgrown structures with nanotubes embedded into GaAs have been obtained. (C) 2000 Elsevier Science B.V. All rights reserved.