Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 13: Poster 1

HL 13.47: Poster

Montag, 26. März 2007, 15:00–17:30, Poster A

Resonant micro-Raman spectroscopy on few InAs quantum dots — •Tim Köppen, Thomas Brocke, Tobias Kipp, Andreas Schramm, Christian Heyn, and Detlef Heitmann — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung der Universität Hamburg, Jungiusstraße 11, 20355 Hamburg, Germany

We investigate the electronic excitations in InAs quantum dots under the exploitation of resonant inelastic light scattering. In contrast to earlier measurements at the E₀ + Δ gap (∼ 1.65 eV) [1], we now excite resonantly at the E₀ gap (∼ 1.2 eV) using a TiSa-laser in the near-infrared regime. Furthermore we now use a microscope setup focussing the exciting laser to a diameter of about 1.8 µm. Although there are still about 250 quantum dots under the laser spot, we observe very few sharp lines of individual quantum dots which arise due to resonant excitation. We can distinguish between Raman signals of electronic excitations and photoluminescense signals which reside in the same energy range.

This project is supported by the Deutsche Forschungsgemeinschaft via SFB 508 “Quantenmaterialien".

[1] T. Brocke et al., Phys. Rev. Lett. 91, 257401 (2003)