Photoreflectance characterization of InAs/GaAs self-assembled quantum dots grown by ALMBE

Abstract. We report on a photoreflectance investigation in the 0.8{1.5 eV photon energy range and at tem-peratures from 80 to 300 K on stacked layers of InAs/GaAs self-assembled quantum dots (QDs) grown by Atomic-Layer Molecular Beam Epitaxy. We observed clear and well-resolved structures, which we attribute to the optical response of dierent QD families. The dependence of the ground state transition energy on the number of stacked QD layers is investigated and discussed considering vertical coupling between dots of the same column. It is shown that Coulomb interaction can account for the observed optical response of QD families with dierent morphology coexisting in the same sample. PACS. 78.66.Fd III-V semiconductors { 73.20.Dx Electron states in low-dimensional structures (superlattices, quantum well structures and multilayers) { 78.40.-q Absorption and reflection spectra: visible and ultraviolet