Branched InAs nanowire growth by droplet confinement

Anisotropy in crystal growth of III-V semiconductor nanowires can be enhanced by the assistance of a liquid particle. During the past decades, selected scientific works have reported a controlled change in the nanowire growth direction by manipulation of the assisting droplet. Although these results are interesting from an engineering point of view, a detailed understanding of the process is necessary in order to rationally design complex nanostructures. In this letter, we utilize our understanding of the growth-assisting droplet to control the morphology and direction of gold-assisted wurtzite-phase InAs nanowires, using controlled droplet displacement followed by resumed growth. By confining the droplet to the nanowire sidewall using zincblende inclusions as barriers, epitaxial growth of horizontal branches from existing nanowires is demonstrated. This is done by tailoring droplet wetting of the nanowire and using identical conditions for the nanowire "stem" and branch growth. This work demonstrates the importance of the droplet dynamics and wetting stability, along with the benefits of crystallographic control, for understanding the growth along different directions. Controlled branched growth is one way to achieve designed nanowire networks.