Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties
HL 91.26: Poster
Donnerstag, 14. März 2013, 16:00–20:00, Poster A
Time-resolved transconductance spectroscopy: Towards all electrical spectroscopy of a single self-assembled quantum dot — •A. Beckel1, D. Zhou1, A. Kurzmann1, B. Marquardt1, A. D. Wieck2, D. Reuter2, M. Geller1, and A. Lorke1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany — 2Chair for Applied Solid State Physics, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
We have shown recently an all electrical preparation and probing of non-equilibrium (i.e. excited) states in an ensemble of self-assembled quantum dots (QDs) using a time-resolved measurement scheme [1,2].
In our high electron mobility transistor structure a two-dimensional electron gas (2DEG) is used as detector and reservoir for the QD states. Using a 2DEG offers sensitive, time-resolved detection via transconductance as well as ideal scaling properties to address a single self-assembled QD.
Electron beam lithography has been applied to process samples containing only ∼ 100 QDs. We present devices and measurements which show enhanced energy resolutions, beyond the inhomogeneous broadening of the QD ensemble. The additional information of the time-resolved measurement is used to attribute the measured spectrum to a set of QD sub-ensemble as well as attribute the tunneling processes to the shell structure of the involved QD states.
[1] B. Marquardt et al., Appl. Phys. Lett. 95, 22113, (2009).
[2] B. Marquardt et al., Nature Commun. 2, 209 (2011).