Dresden 2017 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 33: Quantum Dots: Optical Properties I
HL 33.5: Talk
Tuesday, March 21, 2017, 10:45–11:00, POT 81
Photoelectron generation and capture in the resonance fluorescence of a quantum dot — Annika Kurzmann1, Arne Ludwig2, Andreas D. Wieck2, Axel Lorke1, and •Martin Geller1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Germany. — 2Chair of Applied Solid State Physics, Ruhr-University Bochum, Germany.
The ultimate goal for self-assembled quantum dots (QDs) as single photon sources is a transform-limited photon stream. This goal has not yet been reached, as spectral wandering of the center frequency of the QD transition is still observed. The major sources of this spectral jitter are charge and nuclear spin noise. Charge noise can arise from charging/discharging of trap states that are filled by photoexcited free charge carriers. Furthermore, these photoexcited electrons can relax into the QD, quenching the transitions in a resonant measurement.
Time-resolved resonance fluorescence on a single self-assembled quantum dot (QD) is used to analyze the generation and capture of photoinduced free charge carriers [1]. We directly observe the capture of electrons into the QD as an intensity reduction of the exciton transition and in the appearence of a non-equilibrium trion resonance. The exciton transition is quenched until the captured electron tunnels out of the dot again in the order of milliseconds. Our results demonstrate that even under resonant excitation, excited free electrons are generated and can negatively influence the optical properties of a QD.
[1] A. Kurzmann et al., Appl. Phys. Lett. 108, 263108 (2016).