Polydisperse Au nanoclusters on silicon: fractal aggregates via spinodal decomposition?

Deposition of polydisperse An nanoclusters onto Si via condensation from to luene produces aggregates that may be structurally characterised in terms o f their fractal dimension (Df). Atomic force microscopy reveals a transitio n (as a function of position on the sample surface) from a percolating, gel -like cluster network to isolated, low Df aggregates, highlighting the key role that local cluster concentration plays in determining the morphology o f nanocluster arrays. Although the fractal dimension values measured are co nsistent with nucleation processes, the cluster layer morphologies bear a s triking resemblance to the patterns observed following spinodal decompositi on of polymer blends and binary fluid mixtures. (C) 2001 Elsevier Science B .V. All rights reserved.