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.

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Articles you may be interested inStructure and morphology of the As-rich and the stoichiometric GaAs (114)A surface J. Appl. Phys. 95, 7645 (2004); 10.1063/1.1707212 GaAs(311) templates for molecular beam epitaxy growth: surface morphologies and reconstruction

The GaAs(112)A and (1 :1 :2 :)B surfaces have been prepared by molecular-beam epitaxy (MBE ) and analyzed in situ by low-energy electron diffraction (LEED) and surface core-level spectroscopy of the Ga 3d and As 3d core levels using synchrotron radiation. The morphology of these surfaces has been studied in situ by scanning tunneling microscopy (STM ) and ex situ by scanning electron microscopy (SEM ) and atomic force microscopy (AFM ). Neither of the surfaces is stable, but both decompose into facets under standard MBE preparation conditions. The (112)A surface is covered by regular depressions (inverted pyramids) with a pentagonal base and with side walls formed of low-energy (111), {110}, and as yet unobserved {124} facets.