DIFFUSION-LIMITED AGGREGATION WITH ACTIVE EDGE DIFFUSION

Diffusion-limited aggregation of Ag on Pt(111) and Ag(111) has been studied by scanning tunneling microscopy. In both metal-on-metal systems fractal growth shapes are found in an extended range of deposition temperature and deposition flux. In contrast to classic hit-and-stick diffusion-limited aggregation simulations the average branch width of the ramified aggregates is not monatomic and increases with increasing deposition temperature, which is attributed to an active edge diffusion. From a quantitative analysis of the exponential variation of the branch width with temperature we determine the diffusion constants for edge diffusion. © 1995 The American Physical Society.