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 break-ups 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. We rationalise our results using maps of (i) mean curvatures (and, hence, chemical potentials), and, (ii) Interfacial Shape Distributions (ISDs) (which are based on probability densities associated with different combinations of the two principal curvatures). Finally, we use the moment of inertia tensor to characterise the (non-spherical) shapes and morphologies of (central) nanowire fragments at the junctions.