The importance of high-index surfaces for the morphology of GaAs quantum dots

Results of a combined experimental and theoretical study are presented. GaAs{113} and {112} surfaces have been prepared by molecular beam epitaxy and analyzed in situ by low-energy electron diffraction and ex situ by atomic-force microscopy. The experimentally found structures are in full agreement with surface energies calculated by density-functional theory. The {112} surfaces are unstable under faceting into low-index planes, whereas the {113} surfaces appear as singular surfaces. Particularly, for GaAs(113) the surface energy is comparable with the values for the low-index surfaces. The impacts of these results on the interface between InAs quantum dots and the embedding GaAs matrix are discussed.