Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 36: Quantenpunkte und -dr
ähte: Optische Eigenschaften I

HL 36.11: Vortrag

Donnerstag, 11. März 2004, 12:45–13:00, H17

Resonant Raman Scattering in In(Ga)As/GaAs Quantum Dots — •Alexander Paarmann, Florian Guffarth, Till Warming, Axel Hoffmann, and Dieter Bimberg — TU Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10629 Berlin, Germany

The local vibrational properties of self-organized quantum dots (QDs) are still a pending question. We have performed resonantly excited Raman measurements on self-organized MOCVD and MBE grown In(Ga)As/GaAs QD, which clearly show characteristics of local optical phonons.

Compared to bulk LO- and TO-phonon modes an enhanced exciton-phonon coupling and a low-energy-shift when reaching resonance with the QDs ground-state exciton energy is observed. The local modes depend on QD shape and local strain-field. Flat and pyramidal QDs were examined as well as multiple and single QD layers.

This work was funded by the Nanomat project of the European Commission Growth Programme, contract number G5RD-CT-2001- 00545, Intas project 2001-774, and SFB 296 of DFG.