Macroscopic island formation was studied, during the Stranski-Krastanov growth of Ge on Si(001) surfaces, by means of transmission electron microscopy. An interplay of surface morphology evolution and defect formation during growth was revealed. It was shown that the nucleation of these macro-islands was generally heterogeneous, and was mediated by a particular type of defect which resulted from the coalescence of small faceted islands.

A.Sakai, T.Tatsumi: Physical Review Letters, 1993, 71[24], 4007-10