Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 64: Quantum Dots: Optical Properties I (organized by HL)
TT 64.6: Talk
Wednesday, April 2, 2014, 10:45–11:00, POT 251
Non-resonant and resonant optical spectroscopy of single self-assembled quantum dots, weakly coupled to a two dimensional electron gas — •Annika Kurzmann1, Benjamin Merkel1, Arne Ludwig2, Andreas 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-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum, Germany
Self-assembled quantum dots (QDs) are promising candidates for single-photon sources and as hosts for spin qubits. For such applications, the QDs are often embedded in a diode structure which allows controlled charging by tunneling of electrons from a 3D, n-doped reservoir, with fast tunneling times in the order of nanoseconds. Here we show results from photoluminescence, differential reflection, resonant fluorescence, and correlation measurements on a single InAs QD, coupled weakly (tunneling times in the order of milliseconds) to a two-dimensional electron gas (2DEG).
By tuning the electrical field, we are able to occupy the QDs with single charge resolution and observe different excitonic emission lines simultaneously over a large voltage range under non-resonant excitation. This unusual behavior can be explained by auto- and cross-correlation measurements of the exciton and trion recombination line and resonant optical measurements, which give in sight into the capture rates of electrons and holes into the dot states.