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

TL;DR

This study uses a phase-field model to analyze how surface diffusion influences nanowire junction stability and break-up, revealing key parameters affecting nanowire fragmentation and morphology evolution over time.

Contribution

It introduces a phase-field approach incorporating enhanced surface diffusion to understand nanowire junction stability and break-up mechanisms, highlighting the roles of geometric parameters.

Findings

Junction formation initiates nanowire break-up via sintering.

Break-up driven by Rayleigh instability occurs away from junctions.

Nanowire size, intersection angle, and radii significantly influence break-up kinetics.

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.