Magneto-excitonic states in charge-tunable self-assembled quantum dots

The luminescence spectroscopy of charge tunable self-assembled InAs quantum dots is reviewed. We discuss that for confined excitons charged with more than three electrons in excess the quantum dot state can be resonantly coupled to the two-dimensional continuum of electronic states of the wetting layer. This coupling manifests itself in a magnetic field and is triggered by photon emission. In contrast the neutral, singly and doubly charged exciton have optical spectra consistent with the artificial atom picture.