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HL: Fachverband Halbleiterphysik

HL 64: Poster II

HL 64.41: Poster

Donnerstag, 19. März 2020, 10:00–13:00, P1A

Conductance spectroscopy on quantum dot molecules — •Carsten Ebler, Giang N. Nguyen, Alexander R. Korsch, Andreas D. Wieck, and Arne Ludwig — Ruhr-Universität Bochum, 44801 Bochum, Germany

Quantum dot molecules (QDM) have shown to be a good approach increasing the T2 time in quantum bits [1]. For a controlled charging of QD charge states and a better understanding of the interaction and crosstalk inside the QDM, we use two epitaxially grown self-assembled InAs quantum dot layers (SAQD) in close tunnel contact to each other. We establish the QDM in tunnel contact with an inverted GaAs/Al0.3Ga0.7As HEMT structure containing a 2-dimensional electron gas (2DEG), manipulate the system with electronical and optical pulses and perform time resolved conductance measurements [2] of the 2DEG to readout the charge occupation of the QDMs. The charge state is read out over conductivity changes in the channel of the HEMT and the resulting transient contains multi-exponential components. We make use of the inverse Laplace transformation to distinguish between the different time constants representing tunnel contributions into the different quantum dot layers.

[1] Weiss et. al, PRL 109 (2012) [2] Marquardt et. al, APL 95 (2009)