Polarized cathodoluminescence study of selectively grown self-assembled InAs/GaAs quantum dots

We have examined the optical properties of self-assembled InAs quantum dots (QDs) grown on prepatterned GaAs(001) substrates with polarization sensitive and time-resolved cathodoluminescence (CL) imaging and spectroscopy techniques. The InAs QDs were formed using a novel application in self-assembled molecular beam epitaxial growth, which entailed the growth of InAs on preformed [110]-oriented stripe mesas. Interfacet In adatom migration occurred along the stripe side-walls during growth, enabling the selective formation of linear arrays of InAs QDs on the stripe mesas. The total InAs deposition needed to induce the two-dimensional to three-dimensional morphology change on the stripes is less than that required to initiate QD formation on the unpatterned substrates. The QDs formed on the mesa top were found with a luminescence distribution redshifted relative to QDs in the valley region, indicating that QDs with a larger average size were formed on the mesa top. The lower density of QDs in the valley reg...