Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 7: Quantum dots and wires: Optical properties I
HL 7.7: Vortrag
Montag, 27. März 2006, 11:45–12:00, POT 151
Resonant Rayleigh scattering from single excitons in disordered GaAs/AlGaAs quantum wells — •Daniel Schwedt1, Rico Schwartz1, Heinrich Stolz1, Dirk Reuter2, Andreas Wieck2, Galina Khitrova3, and Hyatt M. Gibbs3 — 1Universität Rostock, Institut für Physik, Universitätsplatz 3, 18051 Rostock — 2Ruhr-Universität Bochum — 3College of Optical Sciences, Tucson, Az.
We report on experiments performed on MBE-grown quantum well samples exhibiting different kinds of disorder such that the excitons become localized either in the nano-roughness of the interfaces or in slightly larger islands of monolayer steps, i.e. interface fluctuation quantum dots. The excitons have been excited resonantly in Brewster geometry and the elastically scattered signal, i.e. resonant Rayleigh scattering (RRS), has been observed in normal direction with microscopic resolution. The limitation of spatial resolution by diffraction is counterbalanced with high spectral resolution limited only by the linewidth of the exciting cw laser (less than 20 µeV in this case) so that the determined RRS spectra break up into single exciton lines. Thus, important sample parameters like the homogeneous exciton linewidth or relative oscillator strengths are directly measureable by a straight forward resonance scan of the excitation energy. Moreover, microscopically resolved RRS may become a tool for determination of the extension of the exciton’s center-of-mass wave functions as well as local energy distribution of the exciton states and such giving insight to the underlying disorder potential.