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 ${\mathrm{Si}}_{1-x}{\mathrm{Ge}}_x$ islands $(0.2<x<\mathrm{}0.6\mathrm{})$ 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.