Phase-field study of surface diffusion enhanced break-ups of nanowire junctions

Abstract

Using a phase-field model which incorporates enhanced diffusion at the nanowire surfaces, we study the effect of different parameters on the stability of intersecting nanowires. Our study shows that at the intersection of nanowires, sintering (curvature driven material flow) leads to the formation of junctions. These junctions act the initiators of nanowire break-up. The subsequent breakups take place due to Rayleigh instability at the arms away from these junctions. Finally, at long time scales, the fragments coarsen due to the differences in sizes. The radii of the nanowires that form the junction, the difference in size of the intersecting nanowires and the angle of intersection play a dominant role in determining the kinetics of break-up while the density of intersections has little or no effect on the kinetics. The surface energy anisotropy makes the nanowires with favourable interfaces stable. However, even in the case of nanowires with anisotropic interfacial energy, the fragmentation behaviour is qualitatively the same in terms of formation of junctions and the first break-up at the junction. Finally, we rationalise our results using maps of Gaussian curvatures (and, hence chemical potentials).