Cyclic growth of strain-relaxed islands

Growth of Ge islands on Si(001) is observed in real time with high spatial resolution, using UHV transmission electron microscopy. We are able to monitor the formation of successive strain-relieving dislocations. The shape of the island oscillates as it grows, with each cycle corresponding to the introduction of one dislocation. Such growth cycles are shown to be a general feature of the growth of strain-relaxed islands, occurring even in equilibrium. © 1994 The American Physical Society.