Classification of the Morphologies and Related Crystal Phases of III–V Nanowires Based on the Surface Energy Analysis

Abstract

Zincblende-wurtzite polytypism in III–V nanowires has been of great interest for a long time. However, full understanding and control over the crystal phase is still lacking. Here, we propose a model for the morphologies and related crystal phases of vapor–liquid–solid III–V nanowires by considering the minimum surface energies of different side wall facets as a function of the droplet contact angle. On the basis of the recent experimental data and earlier theoretical calculations of the surface energies, a simple classification of the possible growth modes is presented. It shows that the wurtzite phase forms in vertical nanowires at intermediate contact angles whereas the zincblende phase is predominant for vertical or inverse-tapered nanowires with a truncated top at larger contact angles. The small stable contact angle corresponds to faulted wurtzite–zincblende intermix. Pure zincblende phase is possible for even smaller contact angles only in the kinetic growth regimes. The wurtzite and zincblende dom...