Solid-state dewetting-mediated aggregation of nanoparticles

Abstract

The deposition of Au onto thin Xe films at a low temperature leads to cluster formation. The subsequent Xe sublimation results in cluster aggregation and delivery to the substrate in a process known as buffer-layer-assisted growth. Previously, this process was described in terms of a diffusion-limited cluster-cluster aggregation process during layer-by-layer desorption of the buffer. Instead, significant diffusion, restructuring, and dewetting of the Xe occur prior to desorption, and this leads to cluster aggregation. Cluster motion and aggregation are driven by capillary forces as the dewetting film retreats and sublimes. Kinetic Monte Carlo simulations reproduce the experimentally observed particle shapes and size distributions, and they provide additional insight into the interaction of the particles with the dewetting front. The presence of nanoscale particles on the film inhibits dewetting and significantly alters the shape of the front.