Island Statistics Reflecting Growth Processes

Abstract

The scaling properties of islands grown during submonolayer thin film deposition have presented a long-standing challenge to theorists. Recently, the capture zone model has been used to obtain a good understanding of the island size distributions for the cases of immobile islands that nucleate above a critical size. What scaling properties exist in other circumstances? I shall discuss two cases: firstly, when monomer evaporation from the substrate is included and, secondly, when the islands have a mobility that is comparable to that of the deposited monomers. With monomer evaporation we find that the island size distributions show approximate scaling with coverage, where the shape of the distribution is indicative of the magnitude of the evaporation rate. In the second case, high island mobility means that a mean-field approach to describing the dynamics is appropriate. Here, there is no scaling of the size distribution, but the variation of the total island density with substrate coverage displays scaling properties that are characteristic of the island mobility. It is thus apparent that different growth processes impact on the island statistics in distinct ways, promising simple diagnostic measures from which experimentalists can determine the dominant growth processes in their systems.