Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 27: Ultrakurzzeitph
änomene II
HL 27.7: Vortrag
Mittwoch, 13. März 2002, 16:00–16:15, H14
Ultralong Dephasing Time in InGaAs Quantum Dots — •W. Langbein1, P. Borri1, S. Schneider1, U. Woggon1, R. L. Sellin2, D. Ouyang2, and D. Bimberg2 — 1Exp. Physik IIb, Universität Dortmund, Otto-Hahn-Str. 4, 44221 Dortmund — 2Institut für Festkörperphysik TU,Hardenbergstrasse 36, D-10623 Berlin
We measure a dephasing time of several hundred picoseconds at low temperature in the ground state transition of strongly confined InGaAs quantum dots, using a highly sensitive four-wave mixing technique [1]. Between 7 and 100 K the polarization decay has two distinct components resulting in a non-Lorentzian line shape with a lifetime-limited zero-phonon line and a broadband from elastic exciton acoustic-phonon interactions. The zero-phonon line-width increases with temperature following an activated behavior of 16 meV activation energy. This is attributed to the phonon-assisted transition from the exciton ground state to an exciton state involving the first excited hole level.
[1] P. Borri et al., Phys. Rev. Lett. 87, 157401 (2001)