Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 42: Quantenpunkte und -dr
ähte: Optische Eigenschaften II
HL 42.2: Vortrag
Donnerstag, 11. März 2004, 15:30–15:45, H13
Inelastic light scattering of few-electron collective excitations in charge-tunable artificial atoms — •T. Brocke1, A. Stührk1, M.-T. Bootsmann1, M. Tews2, B. Wunsch2, D. Pfannkuche2, Ch. Heyn1, W. Hansen1, D. Heitmann1, and C. Schüller1 — 1Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg — 2I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, D-20355 Hamburg
We report the investigation of electronic excitations in InGaAs self-assembled quantum dots using resonant inelastic light scattering. By applying a voltage between a metallic front gate and a back electrode, the dots can be charged with N=1...6 electrons. We observe excitations, which are identified as transitions of electrons from the s to the p shell (s-p transitions) and from the p- to the d-shell (p-d transitions) of the quasiatoms. We find that the s-p transition energy decreases and the observed band broadens, when the p shell is filled with 1 to 4 electrons. By a theoretical model, which takes into account the full Coulomb interaction in the few-electron artificial atom, we can confirm the experimental results to be an effect of the Coulomb interaction in the quantum dot.
This project is funded by the DFG via SFB 508 and SCHU1171/2.