Surface influence on stability and structure of III-V nanorods: First-principles studies

TL;DR

This study uses first-principles calculations to explore how surface properties influence the stability and structure of III-V semiconductor nanorods, revealing phase transitions and surface effects on atomic relaxation.

Contribution

It provides new insights into the surface-driven phase stability and structural variations of III-V nanorods through ab initio methods.

Findings

Surface energies dominate nanorod stability.

Phase transition between zinc-blende and wurtzite structures.

Atomic relaxation reduces bond lengths compared to bulk.

Abstract

We report ab initio investigations of hexagon-shaped, [111]/[0001] oriented III-V semiconductor nanowires with varying crystal structure, surface passivation, surface orientation, and diameter. Their stability is dominated by the free surface energies of the corresponding facets which differ only weakly from those of free surfaces. We observe a phase transition between local zinc-blende and wurtzite geometry versus preparation conditions of the surfaces, which is accompanied by a change in the facet orientation. The influence of the actual III-V compound remains small. The atomic relaxation of nanowires gives rise to smaller bond lengths in comparison to the bulk zinc-blende structures resulting also in somewhat reduced bilayer thicknesses parallel to the growth direction.