Morphological transformation of In_yGa_1-yAs islands, fabricated by Stranski-Krastanov growth

A remarkable change in topology occurs when In_yGa _1-yAs quantum dots, grown by Stranski-Krastanov self-organization, are covered by a thin layer of GaAs. The nano-islands rearrange themselves to form volcano-like islands with distinct, ring-like features. The island topology can be preserved during overgrowth and thus used for the fabrication of ring-shaped quantum structures. The experimental data suggests that two mechanisms, diffusion and dewetting, are driving the transformation from dots to rings.