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

Results of a combined experimental and theoretical study are presented. GaA s{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-f orce microscopy. The experimentally found structures are in full agreement with surface energies calculated by density-functional theory. The {112} su rfaces are unstable under faceting into low-index planes, whereas the {113} surfaces appear as singular surfaces. Particularly, for GaAs(113) the surf ace energy is comparable with the values for the low-index surfaces. The im pacts of these results on the interface between InAs quantum dots and the e mbedding GaAs matrix are discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)02907-2].