Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 35: HL Poster II
HL 35.53: Poster
Mittwoch, 3. April 2019, 17:30–20:00, Poster E
Time-resolved reflectometry measurements on self-assembled quantum dots — •Jakob Penner1, Kevin Eltrudis1, Isabel Oppenberg1, Arne Ludwig2, Andreas D. Wieck2, Martin Geller1, and Axel Lorke1 — 1Faculty of Physics and CENIDE, University Duisburg-Essen, Germany — 2Chair of Applied Solid State Physics, Ruhr-University Bochum, Germany
Time-resolved transconductance measurements on the electron dynamics of self-assembled quantum dots (QDs) [1] can be used to access excited spin- and charge states in an all-electrical measurement [2], an important step towards quantum state manipulation and detection for future quantum information technologies. However, for fast and high-fidelity measurements, the signal-to-noise ratio of the read-out signal is of great importance. Combining transconductance with time-resolved reflectometry in a lock-in measurement scheme promises to significantly increase the signal-to-noise ratio. We use a high-mobility electron transistor (HEMT) with a layer of QDs that are coupled to a two-dimensional electron gas. This allows us to observe the tunneling dynamics between the 2DEG and the QDs in a reflectometry measurement setup. A high-frequency ac driving voltage in combination with a lock-in technique is set to an electrical resonance of an internal LC circuit. The reflected signal depends on the impedance of the sample, where the change in impedance is related the number of electron in the quantum dot layer, hence, to the tunneling dynamics.
[1] B. Marquardt. et al., Nature Commun. 2, 209 (2011).
[2] K. Eltrudis et al., Appl. Phys. Lett. 111, 092103 (2017).