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14 June 2004 Dephasing processes in InGaAs quantum dots and quantum-dot molecules
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The dephasing time in semiconductor quantum dots and quantum-dot molecules is measured using a sensitive four-wave mixing heterodyne technique. We find a dephasing time of several hundred picoseconds at low temperature in the ground-state transition of strongly-confined InGaAs quantum dots, approaching the radiative-lifetime limit. Between 7 K and 100 K the polarization decay has two distinct components resulting in a non-Lorentzian lineshape with a zero-phonon line and a broad band from elastic exciton-acoustic phonon interactions. On a series of InAs/GaAs quantum-dot molecules having different interdot barrier thicknesses a systematic dependence of the dephasing dynamics on the barrier thickness is observed. The results show how the quantum mechanical coupling of the electronic wavefunctions in the molecules affects both the exciton radiative lifetime and the exciton-acoustic phonon interaction.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Paola Borri, Wolfgang W. Langbein, S. Schneider, Ulrike Woggon, Markus Schwab, Manfred Bayer, Roman L. Sellin, Dongxun Ouyang, Dieter Bimberg, S. Fafard, Zbigniew R. Wasilewski, and Pawel Hawrylak "Dephasing processes in InGaAs quantum dots and quantum-dot molecules", Proc. SPIE 5361, Quantum Dots, Nanoparticles, and Nanoclusters, (14 June 2004);

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