Interatomic potential for atomistic simulation of self-catalyzed GaAs nanowires growth

Semiconductor nanowires are long time candidates for numerous applications. Complete understanding of their most common growth process (vapour-liquid-solid), however, is essential in order to achieve the crystalline quality that applications demand. To date, most of the information gathered to understand vapour-liquid-solid growth comes from ex situ and in situ electron microscopy images. Still, those approaches might miss some important features due to time and length scales involved. In this sense, computational simulations can provide additional insights into the process. Yet, so far, no computational simulation was able to consistently reproduce the growth of more than one monolayer of a semiconductor nanowire through the vapour-liquid-solid method. By using a force matching software (PotFit), we developed a new GaAs interatomic potential for molecular dynamics simulations. Our potential can reproduce several features of the growth of self-catalyzed GaAs nanowires, including: formation of zinc blende and wurtzite layers, layer-by-layer formation of the solid phase, b-polar surface growth preference and the dependency between growth rate and precursor flow.