A study of the surface morphology of homoepitaxial (001) surfaces, by means of atomic force microscopy in air, revealed the re-entrant nature of the mounding behavior at low growth temperatures. A transition from statistical roughening, to organized mound formation, was observed as the growth temperature was reduced. It was shown, by means of growth simulations, that the observed morphology was compatible with anisotropic adatom diffusion in the presence of an Ehrlich-Schwoebel barrier. The mechanism which led to this type of adatom kinetics at low temperatures was explained in terms of condensing As acting as a surfactant at the surface.

Reentrant Mound Formation in GaAs(001) Homoepitaxy Observed by ex situ Atomic Force Microscopy G.Apostolopoulos, J.Herfort, L.Däweritz, K.H.Ploog, M.Luysberg: Physical Review Letters, 2000, 84[15], 3358-61