Position controlled self-catalyzed growth of GaAs nanowires by molecular beam epitaxy

TL;DR

This paper demonstrates position-controlled growth of GaAs nanowires via molecular beam epitaxy using a self-catalyzed, Ga-assisted method with nano-patterned substrates, revealing growth rate dependencies on interwire spacing.

Contribution

It introduces a nano-patterning technique for precise position control of self-catalyzed GaAs nanowires during molecular beam epitaxy, highlighting the influence of interwire spacing on growth conditions.

Findings

Nanowires exhibit hexagonal cross-sections with {110} facets.

Growth rate decreases with increasing interwire distance due to changing III/V ratio.

Crystallize predominantly in zincblende structure.

Abstract

GaAs nanowires are grown by molecular beam epitaxy using a self-catalyzed, Ga-assisted growth technique. Position control is achieved by nano-patterning a SiO2 layer with arrays of holes with a hole diameter of 85 nm and a hole pitch varying between 200 nm and 2 \mum. Gallium droplets form preferentially at the etched holes acting as catalyst for the nanowire growth. The nanowires have hexagonal cross-sections with {110} side facets and crystallize predominantly in zincblende. The interdistance dependence of the nanowire growth rate indicates a change of the III/V ratio towards As-rich conditions for large hole distances inhibiting NW growth.