Nucleation Transitions for InGaAs Islands on Vicinal (100)GaAs

Differences in InGaAs island nucleation on vicinal (100) GaAs surfaces as a function of miscut angle are presented. Arrhenius plots of saturation island densities show changes in activation energy and critical cluster size, which are interpreted as resulting from nucleation through different mechanisms: homogeneously (on terraces) and heterogeneously on monatomic and multiatomic steps. Furthermore, a link between step separation and island uniformity is observed. Step availability is found to be a major determinant of island uniformity at temperatures where clusters are not mobile.