Formation of Wurtzite InP Nanowires Explained by Liquid-Ordering

We report an in situ surface X-ray diffraction study of liquid AuIn metal alloys in contact with zinc-blende InP (111)B substrates at elevated temperatures. We observe strong layering of the liquid metal alloy in the first three atomic layers in contact with the substrate. The first atomic layer of the alloy has a higher indium concentration than in bulk. In addition, in this first layer we find evidence for in-plane ordering at hollow sites, which could sterically hinder nucleation of zinc-blende InP. This can explain the typical formation of the wurtzite crystal structure in InP nanowires grown from AuIn metal particles.