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 refl ections 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 f acets corresponding to a family of four {136} planes. The determined s tructure, which possesses C-2 upsilon symmetry, is quite different bot h from square-base pyramidal geometries which have been assumed in rec ent electronic structure calculations, and from previously proposed st ructures which have been based upon incomplete reflection high energy electron diffraction data. (C) 1998 American Institute of Physics.