Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 4: Quantenpunkte und -dr
ähte: Optische Eigenschaften I
HL 4.4: Vortrag
Freitag, 4. März 2005, 11:30–11:45, TU P-N201
Recombination rates of excitons and biexcitons in quantum dots — •Michael Wimmer1, John Shumway2, and S. V. Nair3 — 1Institut für Theoretische Physik, Universität Regensburg — 2Department of Physics and Astronomy, Arizona State University — 3Centre for Advanced Nanotechnology, University of Toronto
The properties of interacting electron-hole pairs in a quantum dot are strongly
affected by quantum correlations.
Important examples include binding energies as well as radiative decay rates.
Measurements on the biexciton recombination rate in different material systems
lie in the theoretically predicted range of one to two times the rate of single exciton
recombination [1].
Recently, configuration interaction (CI) studies have shown that the radiative
decay rates depend strongly on the quantum dot size [2]. However,
our studies indicate that energy and recombination rates do not converge simultaneously
in CI calculations, leading to a systematic underestimation of the decay rate.
We have developed a path integral Monte Carlo (PIMC) technique that does not suffer from this problem.
This technique is applied to realistic three-dimensional models of self-assembled
quantum dots for different materials. We find that radiative recombination rates of
typical dots lie in the cross-over regime between strong and weak confinement
and compare these results with experiment.
References:
C. Santori et al. PRB 65, 073310 (2002), G. Bacher
et al. PRL 83, 4417 (1999), R. Thompson et al.
PRB 64, 201302 (2001)
S. Corni et al. PRB 67, 045313 (2003)