SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 24: Quantum dots: Optics
HL 24.12: Talk
Wednesday, March 29, 2023, 12:45–13:00, POT 151
The role of charge transfer for light emission from excitonic complexes in a single quantum emitter — •Marcel Zöllner1, Fabio Rimek1, Hendrik Mannel1, Andreas D. Wieck2, Arne Ludwig2, Martin Geller1, and Axel Lorke1 — 1University of Duisburg-Essen, Germany — 2Ruhr-University Bochum, Germany
Due to the non-radiative Auger recombination in self-assembled quantum dots [1], the light emission of the trion X− is reduced. However, for devices and statistical analyses, such as random telegraph signals, the amount of quantum dot photons is of great importance.
With time-resolved resonance fluorescence (RF) measurements, we investigate a comparatively small quantum dot, where we can tune the rate of the electron tunneling from the back contact into the quantum dot by increasing the gate voltage. This results in an up to two orders of magnitude higher trion intensity. Due to the large gate voltages (i.e. energetically strongly tilted conduction band) the electrons can easily overcome the tunnel barrier. Thus, the electron tunneling becomes the dominant effect and charges the quantum dot significantly faster than the Auger effect can discharge it.
Our results indicate that thin tunneling barriers, which can quickly equilibrate states in a quantum dot, make its radiative recombination more resilient against spurious charge transfer (Auger, electron capture, internal photoemission). However, this improvement goes along with a short coherence time.
[1] P. Lochner et al., Phys. Rev. B 103, 075426 (2021).