STABLE AND METASTABLE INGAAS GAAS ISLAND SHAPES AND SURFACTANT-LIKE SUPPRESSION OF THE WETTING TRANSFORMATION/

Contrasting behaviors are observed in InGaAs/GaAs island formation dur ing 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 incohe rent islands, and dissimilar morphologies upon annealing. The latter e xperiments show that small lens-shaped islands can be found in equilib rium if InGaAs surface energies are minimized, leading to the conclusi on that AsH3 can raise surface energies and act as an impurity-free '' morphactant.''