Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 60: Quantum dots: Transport
HL 60.2: Talk
Wednesday, March 18, 2015, 17:30–17:45, EW 203
Optical detection of single-electron tunneling dynamics in self assembled quantum dots — •Annika Kurzmann1, Benjamin Merkel1, Arne Ludwig2, Andreas D. Wieck2, Axel Lorke1, and Martin Geller1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany — 2Chair of Applied Solid State Physics, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany
The tunneling dynamics of charge carriers into self-assembled quantum dots (QDs) have been studied using electrical measurements like transconductance spectroscopy. However, these techniques are still limited to measurements of an ensemble of QDs, i.e. the dynamics of single electron tunneling into a single QD has not been observed yet.
Here, for the first time, we demonstrate that we are able to study the electron tunneling between a single self-assembled QD and a 3D back contact, using resonance fluorescence as detection scheme. The QD is embedded in a diode structure, which allows controlled charging and discharging of the QD with single electron resolution. We apply voltage pulses to the top-gate contact and measure the resonance fluorescence signal, while electrons tunnel into or out of the QD. Using this new time-resolved measurement technique, we investigate the relation between the tunneling times into the QD and the chemical potential in the back gate. An even more detailed understanding of the tunneling processes between QDs and a charge carrier reservoir can be achieved by measuring the telegraph noise in the resonance fluorescence signal, when the states with occupation number 0 and 1 are degenerate.