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HL: Fachverband Halbleiterphysik

HL 8: Poster Session II

HL 8.5: Poster

Dienstag, 28. September 2021, 10:00–13:00, P

Capacitance-voltage spectroscopy on quantum dots without electronic wetting layer states — •Ismail Bölükbasi, Sven Scholz, Andreas D. Wieck, and Arne Ludwig — Ruhr-Universität Bochum, D-44780 Bochum, Germany

Quantum dots have interesting physical properties and allow research in zero dimensional systems. They are used in modern displays and may become important for the progress of semiconductor and information technology in the form of qubits in quantum computers and quantum memories or sources of high-fidelity single photons in quantum communication applications.

Quantum dots are created by molecular-beam-epitaxy (MBE) in the so-called Stranski-Krastanov growth mode. InAs arranges epitaxially on GaAs in a strained layer of up to 1.5 monolayers without relaxation before nucleation of coherently strained islands takes place. This layer remains between the islands and is called the wetting layer.

We find that a monolayer of AlAs deposited after the growth of the quantum dots can suppress certain states in this wetting layer [1], allowing to purify their photoluminescence spectra from electronic contributions such as for example a two-dimensional-electron gas would induce. Capacitance-voltage and photoluminescence measurements are carried out to investigate the effects of this monolayer of AlAs on the physical properties of the quantum dots and the modified charging behaviour around flat band conditions.

[1] Löbl, M. C. et al. Excitons in InGaAs quantum dots without electron wetting layer states. Commun. Phys. 2, 93 (2019).