Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 3: Heterostrukturen I
HL 3.8: Vortrag
Montag, 11. März 2002, 12:15–12:30, H14
Highly Resolved Resonant Rayleigh Scattering from GaAs Quantum Wells — •Daniel Schwedt1, Christoph Nacke1, Heinrich Stolz1, Soheyla Eshlaghi2, Dirk Reuter2, and Andreas Wieck2 — 1Universität Rostock, Fachbereich Physik, Universitätsplatz 3, 18051 Rostock — 2Ruhr-Universität Bochum, Angewandte Festkörperphysik, Universitätsstr. 150, 44780 Bochum
We report investigations of resonant Rayleigh scattering spectra from high quality GaAs quantum wells (20nm; linewidth Δ E<200 µ eV) grown by MBE which were irradiated with a cw Ti-Sapphire laser. The resulting spectra show a δ-like Rayleigh peak which is due to coherent scattering and a Lorentzian luminescence line.
For a theoretical discription the excitons were treated as an ensemble of spin degenerated three-level-systems. The resonance frequencies of which were taken to be Gaussian distributed due to inhomogeneous broadening from disorder. This results in scattering spectra which show the same characteristic features as the measured ones. Using that model we are able to deduce both the homogeneous and inhomogeneous linewidth from the scattering spectra. These results were compared with those obtained from a four-wave mixing experiment and good agreement was found.
Furthermore, the polarization properties of the Rayleigh scattered signal have been examined and depicted as polar plots of polarized intensity. Therefrom we found the excitation dipoles almost perfectly aligned along [110]-directions. These results are similar to those obtained by speckle analysis.