Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 12: Quantenpunkte und -dr
ähte: Optische Eigenschaften II
HL 12.2: Vortrag
Freitag, 4. März 2005, 15:15–15:30, TU P-N201
Absorption and Emission Spectroscopy on a Single Charge-Tunable Quantum Dot — •Martin Kroner1, Alexander Högele1, Stefan Seidl1, Richard J. Warburton2, Brian D. Gerardot3, Pierre M. Petroff 3, and Khaled Karrai1 — 1Center for NanoScience and Department für Physik, Ludwig-Maximilians-Universität, Munich, Germany — 2Department of Physics, Heriot-Watt University, Edinburgh, UK — 3Materials Department, University of California, Santa Barbara, California 93106, USA
We have recently reported resonant interband absorption in the excitonic ground state of a single self-assembled InAs/InGaAs quantum dot [1]. The resonant interband transitions are observed directly as a reduction in the transmission signal when the exciton energy is tuned into resonance with a narrow band laser. This fairly new high-resolution laser spectroscopy technique profits from coherent creation of excitonic states in a single quantum dot, hence providing information about the oscillator strength as well as the lifetime. The excitonic state in the dot can be tuned from neutral to charged, simply by applying a gate voltage, as the dots are embedded in a field effect structure [2]. We measured absorption as well as photoluminescence spectra of the same quantum dot. Comparing these datasets reveals new insight into the electronic states of a quantum dot.
[1] A. Högele et al., Physica E 21 (2004); A. Högele et al., to appear in PRL (2004). [2] R. J. Warburton et al., Nature 405 (2000).