Lateral ordering of Ge islands on Si mesas made by selective epitaxial growth

The lateral ordering of Ge islands on Si mesa edges is driven by the presence of tensile strain at the periphery of the mesas. While random islands on (001) areas have a bi-modal distribution, ordered islands on {hkl} facets are mainly mono-modal. This is due to the island–island interaction in the one-dimensional row. As a consequence of the narrower size distribution of ordered islands, the photoluminescence (PL) peaks are better resolved. It is shown that the evolution of emission intensity with temperature and island shape is governed by hole transfer between wetting layer and ordered islands.