InAs quantum dots grown by molecular beam epitaxy on GaAs (211)B polar substrates

Abstract

InAs nanostructures were grown by molecular beam epitaxy on GaAs (211)B at temperatures between 400-530 °C and growth rates that were varied between 0.1 to 0.02 mono-layers (ML) per second. For temperatures up to 500 °C we obtain pyramidal-shaped InAs quantum dots with average heights between 3 and 7 nm while at 530 °C the dots become elongated, higher and are self organized into dashes along a specific crystallographic direction. Photoluminescence (PL) spectra taken at 18 K reveal in the QD samples grown at 500 °C a broad (55 meV FWHM) PL peak at 1.27 eV, associated with the QD layer. The PL peak blue shifts noticeably (∼7 meV) upon increasing power of excitation, as a consequence of the strain induced electric field that exists in the (211)B direction. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.