Determination of the shape of self-organized InAs/GaAs quantum dots by reflection high energy electron diffraction

We report a reflection high energy electron diffraction study of InAs self-organized quantum dots grown on GaAs (001). We observe facet reflections along the [3 (1) over bar 0] and [1 (3) over bar 0] azimuths, which indicate that the quantum dot shape is pyramidal with bounding facets corresponding to a family of four {136} planes. The determined structure, which possesses C-2 upsilon symmetry, is quite different both from square-base pyramidal geometries which have been assumed in recent electronic structure calculations, and from previously proposed structures which have been based upon incomplete reflection high energy electron diffraction data. (C) 1998 American Institute of Physics.