MODEL INCORPORATING DEPOSITION, DIFFUSION, AND AGGREGATION IN SUBMONOLAYER NANOSTRUCTURES

We propose a model for describing diffusion-controlled aggregation of particles that are continually deposited on a surface. The model incor porates deposition, diffusion, and aggregation. We find that the diffu sion and aggregation of randomly deposited particles ''builds'' a wide variety of fractal structures, all characterized by a common length s cale L1. This length L1 scales as the ratio of the diffusion constant over the particle flux to the power 1/4. We compare our results with s everal recent experiments on two-dimensional nanostructures formed by diffusion-controlled aggregation on surfaces.