Spatially resolved magneto-optics on confined systems

We report about spatially resolved magneto-optical experiments on two different confined semiconductor systems. Using near-held spectroscopy through AFM-written shadow masks we have investigated the optical properties of single self-assembled InGaAs quantum dots as a function of excitation power and magnetic field. This allows us to identify and fully resolve diamagnetic/orbital effects and the Zeeman splitting in the ground state and excited state of a given quantum dot. Further we report on the transport properties of minority holes ina high mobility two-dimensional electron gas at finite electric fields and high magnetic fields. Making use of spatially resolved optical excitation and detection we study the propagation of optically excited minority holes within the sea of a drifting two-dimensional electron gas. At high magnetic fields we observe an E x B drift of holes which is dominated by the Hall-field of the electron gas. At the edge of the Hall-bar, we observe edge state transport of holes via skipping orbits opposite to the direction of the initial Ex B drift. (C) 1998 Elsevier Science B.V. All rights reserved.