Fractal growth of two-dimensional islands: Au on Ru(0001)

Abstract

The two-dimensional growth of Au on Ru(0001) in the submonolayer range has been investigated with scanning tunneling microscopy. Upon deposition at room temperature, highly dendritic islands of one layer thickness grow on large Ru terraces. These irregular island shapes are removed upon annealing to 650 K. The dendritic islands exhibit a fractal character, and a dimensional analysis yields a fractal dimension of 1.72\ifmmode\pm\else\textpm\fi{}0.07. The results are in quantitative agreement with a two-dimensional diffusion-limited-aggregation growth mechanism.