From Droplets to Nanowires: Dynamics of Vapor-Liquid-Solid Growth

Starting with a liquid eutectic droplet on a surface, we calculate its dynamical evolution into an epitaxial nanowire via the vapor-liquid-solid growth process. Our continuum approach incorporates kinetic effects and crystalline anisotropy in a natural way. Some realistic features appear automatically even for an isotropic solid, e.g., the tapered wire base. Crystal anisotropy leads to a richer variety of morphologies. For example, sixfold anisotropy leads to a wire shape having broken symmetry and an intriguing resemblance to the $⟨110⟩$-oriented Si wires seen in Au-catalyzed growth on Si (111), while higher symmetry leads to a shape more like $⟨111⟩$ Si wires.