Nucleation and cluster size in ultra-thin metal deposits

Metal deposits in early stages of nucleation and growth on weakly interacting supports consist of isolated small metal clusters. Such ultrathin deposits are often used for studying the physical and chemical properties of small metal aggregates. By surveying a large number of experimental results for a variety of nucleation systems and by comparing with predictions from nucleation theory, we have established that preferred nucleation on surface defects under conditions of high supersaturation will produce large number densities (N) of small clusters. Under these deposition conditions the resulting cluster size distributions are narrow and change only slowly with further growth.