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HL: Halbleiterphysik
HL 26: Symposium: Spectroscopy of Single Quantum Dots
HL 26.5: Fachvortrag
Thursday, March 29, 2001, 12:30–13:00, S2
Optical spectroscopy on single quantum dots: Charged excitons — •Frank Findeis1, Martin Baier1, Eric Duijs1, Evelin Beham1, Max Bichler1, Artur Zrenner1, Ulrich Hohenester2, and Elisa Molinari2 — 1Walter Schottky Institut, Technische Universität München, am Coulombwall, D-85748 — 2Instituto Nazionale per la Fisica della Materia (INFM) and Dipartimento di Fisica Universita di Modena e Reggio Emilia, Via Campi 213/A, 41100 Modena, Italy
Single self-assembled quantum dots are among the most widely studied systems in the field of modern solid state spectroscopy. The experimental preparation of specific charged exciton states in a single quantum dot can be realized by bias controlled single electron charging and can be probed by optical spectroscopy. With respect to neutral single exciton configurations the optical response of charged exciton complexes is modified due to few particle interactions of the carriers confined in the quantum dot. As a consequence of these renormalization effects we observe different emission energies for neutral, single, and double charged excitons in single quantum dot spectroscopy. A quantitative comparison of the experimentally determined binding energies for single and double charged excitons with theoretical model calculations demonstrates a substantially stronger confinement of the hole wave function with respect to the electron wave function. The application of magnetic field to charged exciton complexes opens the interesting field of spin physics in quantum dots. The observation of spin dependent tunneling from singlet and triplet states nicely demonstrates that spin related phenomena can be considerably enhanced in QDs.