Formation of III-V Compound Semiconductor Nanowires and a Crystal Structure Change between Zincblende and Wurtzite(<Special Issue> Stable or Metastable: Zinc Blende and Wurtzite Structures)

Abstract

GaAs and InAs nanowires were selectively grown by using metal-organic vapor-phase epitaxy. The nanowires were as thin as several tens to several hundreds nanometers and as long as several micronmeters. Scanning electron microscope observations showed that the growth direction of nanowires was parallel to the <111> B crystallographic orientation. It was found by a transmission electron microscopy analysis that the crystal structure of the GaAs nanowire was zincblende with rotational twins around the <111> axis. For the GaAs nanowires, the density of twins along the <111> direction increased as the nanowire diameter decreased. The growth mechanism was understood based upon a model that the GaAs nanowire was composed of stacked thin-layers with interfaces containing rotational twins.