Morphology of ramified islands in growth of Ge on Si(1 1 1) using Pb as surfactant

Pb mediated growth of Ge on Si(1 1 1) reveals features different from those observed in growth with no surfactant. In particular there is a transition in island shape, from compact to fractal-like, due to temperature. This transition in island morphology is examined here by analysing the structure factor and its scaling properties. The maxima of the structure factor obey a power law, but no universal shape of the scaling function could be found.