Positioning of InAs quantum dots on sub-250 nm facets using selective area epitaxy

Using oxide-patterned substrates, we have selectively grown GaAs mesas with (100) top facets ranging from several /spl mu/m to less than 250 nm in width and InAs quantum dots (QDs) on top of these facets. For a given total InAs coverage, the dot density varies with the facet width. The QDs also tend to form at the facet edges. These observations suggest a strong surface diffusion effect of In-containing species adsorbed on the various GaAs facets of a mesa. By designing the oxide pattern in an appropriate manner, a two-dimensional array of QDs could be positioned in a pre-determined configuration at specific wafer locations.