Self-assembled ge nanocrystals on BaTiO(3)/SrTiO(3)/Si(001)
21 January 2008
The structure of Ge nanocrystals (NC) grown on BaTiO(3) (BTO)/SrTiO(3)/Si(001) is studied by high resolution transmission electron microscopy. The Ge NC are fully relaxed with {111}, {112}, {110}, and {113} planes parallel to the interface. These orientations allow to align one Ge 110 > in-plane direction with one BTO 100 > in-plane direction leading to a minimization of the mismatch in the BTO 100 > direction. Surprisingly, no NC with {100} planes parallel to the interface, leading to a minimization of the mismatch along the two BTO 100 > in-plane directions, are observed. This is interpreted in terms of surface energy minimization.