Growth and characterization of defect free GaAs nanowires

Most III-V compound semiconductor nanowires seeded by metal particles grow preferentially in a (over bar 1 over bar 1 over bar 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 < 111 > A direction (A wires). One novelty is that a {111} A growth plane, like a {over bar 1 over bar 1 over bar 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 {11 over bar 2} and three {11 over bar 2} side facets. A wires, on the other hand, have only three major side facets which are of the {11 over bar 2} type, giving them a triangular cross section. (c) 2005 Elsevier B.V. All rights reserved.