Instability-driven SiGe island growth.

Three-dimensional islanding is generally assumed to proceed through nucleation and growth. Here we present studies showing the growth of Si1-xGex islands (0.2<x<0.6) without nucleation. Rather, a strain-driven growth instability induces a network of elevated cells, where the angle of elevation self-limits when 105 facets form pyramidal islands. These strain-modulated surfaces may serve as a template for the spatially controlled growth of quantum dot ensembles.