Few-Particle Effects in Self-Organized Quantum Dots

Abstract

Few-particle effects are investigated both experimentally and theoretically for self-organized quantum dots (QDs). The actual confinement potential, reflecting the structure-dependent low-symmetry and inhomogeneous strain, is demonstrated to have a strong impact on the few-particle states. Eight-band k·p calculations for the InAs/GaAs model system indicate both binding and anti-binding biexciton states depending on the separation of the electron and hole wave functions. Single-dot experiments on CdSe/ZnSSe QDs enable the identification of the neutral and charged exciton and biexciton states and demonstrate a large variation of the corresponding binding energies attributed to the variation of the structural properties of the probed QDs. First eight-band k·p model calculations for epitaxial CdSe QDs demonstrate a pronounced influence of the Cd-concentration. Finally, lateral energy transfer processes originating at weakly localizing Cd-fluctuations are identified in time-resolved experiments.