Near-surface InAs/GaAs quantum dots with sharp electronic shells

The interaction between zero-dimensional states and surface states is studied using near-surface quantum dot (QD) ensembles with well-defined electronic shells. The inhomogeneous broadening of self-assembled InAs/GaAs QDs increases from similar to 30 to more than similar to 46 meV as the distance of the QDs from the surface is changed from 100 to 5.0 nm. Simultaneously, a decrease of the radiative recombination intensity by similar to 3 orders of magnitude, and a red-shift of similar to 65 meV are observed. For QDs capped with less than similar to 10 nm, remarkable charge transfers between the QD and surface states lead to optical memory effects lasting over time-scales of several minutes. [S0003-6951(00)02619-X].