Optical properties of self-assembled InAs quantum dots grown on GaAs(211)Asubstrate

We have investigated the photoluminescence (PL) and growth properties of se lf-assembled InAs/GaAs quantum dots (QD) grown on (211)A-oriented GaAs subs trate in a low coverage region. At the onset of the QD formation in the Str anski-Krastanov mode, structures of QD on (211)A substrate were quite diffe rent from those on (100) substrate. The uniformity of size distribution was better and the density was higher than that grown on (100) substrate. We f ound a PL peak at 1.32 eV when the InAs coverage was 1.57 ML. Another PL pe ak gradually appeared at 1.37-1.42 eV with increasing InAs coverage. The pe aks at 1.32 and 1.37-1.42 eV were attributed to the emission from a defect- related QD and a typical QD, respectively. When the InAs coverage exceeded 1.89 ML, the QD density decreased with increasing InAs coverage, due to the coalescence of QD. The samples studied here showed PL spectra having a lar ger intensity and narrower full width at half-maximum compared with that gr own on (100) substrate. (C) 2000 Elsevier Science B.V. All rights reserved.