A study was made of the self-induced growth of vertically aligned (i.e. along the [111] direction), free-standing InAs nanowires on Si(111) substrates by solid-source molecular beam epitaxy. Use of an ultra-thin amorphous SiOx mask on Si(111) facilitated epitaxial InAs nanowire growth, as confirmed by high-resolution X-ray diffraction 2θ–ω scans and transmission electron microscopy. Depending on growth temperature (in the range of 400–520C) substantial size variation of both nanowire length and diameter was found under preservation of uniform, non-tapered hexagon-shaped geometries. The majority of InAs nanowires exhibited phase-pure zincblende crystal structure with few defective regions consisting of stacking faults. Photoluminescence spectroscopy at 20K revealed peak emission of the InAs nanowires at 0.445eV, which was ~30meV blue-shifted with respect to the emission of the bulk InAs reference due to radial quantum confinement effects.

Self-Induced Growth of Vertical Free-Standing InAs Nanowires on Si(111) by Molecular Beam Epitaxy. G.Koblmüller, S.Hertenberger, K.Vizbaras, M.Bichler, F.Bao, J.P.Zhang, G.Abstreiter: Nanotechnology, 2010, 21[36], 365602