Key parameters for the formation of II-VI self-assembled quantum dots

To account for the occurrence or absence of the Stranski-Krastanow (SK) transition (two-dimensional to three-dimensional change (2D-3D) of surface morphology) during the epitaxial growth of various lattice-mismatched semiconductor systems, we present a simple equilibrium model taking into account not only the lattice mismatch, but also the dislocation formation energy and the surface energy. The model demonstrates the importance of these parameters especially for II-VI systems such as CdTe/ZnTe and CdSe/ZnSe. For II-VIs indeed, as misfit dislocations are easier to form than in III-Vs (such as InAs/GaAs) or IV systems (Ge/Si), the 3D elastic transition is short-circuited by the plastic transition. Nevertheless, by lowering surface energy, telluride and selenide quantum dots can also be grown as predicted by our model and as evidenced experimentally by both reflection high-energy electron diffraction (RHEED) and optical measurements