Photoluminescence Study of InAs/AlAs Quantum Dots

Abstract

Self-organized InAs quantum dots (QDs) embedded in an AlAs matrix are investigated by photoluminescence (PL) and photoluminescence excitation spectroscopy (PLE). For InAs coverage of about 2.0 ML, a PL peak is observed at energies slightly below 1.6 eV and attributed to radiative recombination from the QD ground states. At higher excitation intensity two additional peaks occur at 80 and 140 meV above the ground state, which we attribute to PL from excited QD states. Transmission electron microscopy (TEM) images show a high QD density of 1 × 1012 cm—2 resulting in small inter-dot distances, which hints to lateral coupling of the QDs.