Domain competition during ballistic deposition: Effect of surface diffusion and surface patterning

Abstract

We investigate domain competition occurring during aggregate growth under ballistic deposition on a one-dimensional substrate by kinetic Monte Carlo simulations. In order to capture adsorbate molecules being deposited vertically, domains grow tall by extending their branches laterally and suppress the growth of neighboring short domains. When molecules are deposited on a flat substrate and frozen at the deposition site, the population density of domains, ρ, decreases by a power law as ρ ∼ h(-2/3) at height h. In contrast, if the effect of surface diffusion is taken into account, the domain density decreases rapidly as ρ ∼ 1/h. On a substrate patterned with an array of nanopillars, domains growing from pillar tops tend to envelop those growing from gaps between pillars. To completely suppress the growth of domains in gaps, pillar periodicity λ should be smaller than a critical value λ(c). We estimate this value approximately using the slope angle and the aspect ratio of a single isolated domain.