Growth and characterization of defect free GaAs nanowires

Most III–V compound semiconductor nanowires seeded by metal particles grow preferentially in a 〈1¯1¯1¯〉B direction (B wires) and most commonly with many stacking faults perpendicular to the growth direction. If growth proceeds in an alternate direction, defect-free growth has been observed. We present experimental results for the growth of GaAs nanowires in a previously uninvestigated growth direction, a 〈1 1 1〉A direction (A wires). One novelty is that a {1 1 1}A   growth plane, like a {1¯1¯1¯}B, is a close packed plane where the stacking sequence can be interrupted forming stacking faults, but unlike the B wires the A wires lack stacking faults. It is also observed that, when grown under equivalent conditions, the growth rate of the A wires is approximately twice that of the B wires. Additionally, B   wires have a hexagonal cross section with three {112¯} and three {1¯1¯2} side facets. A   wires, on the other hand, have only three major side facets which are of the {112¯} type, giving them a triangular cross section.