Stable and metastable InGaAs/GaAs island shapes and surfactantlike suppression of the wetting transformation

Contrasting behaviors are observed in InGaAs/GaAs island formation during vapor phase epitaxy: variation of group V partial pressures gives different critical thicknesses for the onset of the Stranski-Krastanow transformation, surface coverages, ratios between coherent and incoherent islands, and dissimilar morphologies upon annealing. The latter experiments show that small lens-shaped islands can be found in equilibrium if InGaAs surface energies are minimized, leading to the conclusion that AsH3 can raise surface energies and act as an impurity-free "morphactant."