Freiburg 2019 – wissenschaftliches Programm
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FM: Fall Meeting
FM 30: Quantum Sensing: Applications I
FM 30.3: Talk
Dienstag, 24. September 2019, 14:45–15:00, Aula
Quantum dots as charge detectors for nanoscale defect tomography — •Jens Kerski1, Pia Lochner1, Arne Ludwig2, Andreas D. Wieck2, Annika Kurzmann1, Axel Lorke1, and Martin Geller1 — 1Faculty of Physics and CENIDE, University Duisburg-Essen, Germany — 2Chair of Applied Solid State Physics, Ruhr-University Bochum, Germany
Self-assembled semiconductor quantum dots (QDs) can be used as single-photon sources in visionary applications in quantum information technologies. However, spin and charge noise in the vicinity destroy the needed Fourier-transform limited linewidth [1].
In this contribution, we use a single quantum dot as a nanoscale electrometer to investigate the charging process of individual defects with electrons from the nearby n-doped back contact. Spectral and time-resolved resonance fluorescence measurements allow us to identify four nearby defect states by small shifts in the resonance energy of the exciton transition [2]. From the occupation probability of the individual states, the position of these defects in the growth direction, as well as their binding energy were determined. Their spatial position allowed to identify the states as defects.
Our results give rise to further investigations, e.g. triangulation of individual defects using multiple QDs, optical transport measurements at a single QD [3] and nanoscale low level transient spectroscopy.
[1] A. V. Kuhlmann et al., Nature Physics 9, 570-575 (2013).
[2] J. Houel et al., Phys. Rev. Lett. 108, 107401 (2012).
[3] A. Kurzmann et al., Phys. Rev. Lett. in press (2019).