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HL: Fachverband Halbleiterphysik

HL 64: Poster II

HL 64.43: Poster

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

Capacitance-voltage spectroscopy on no-wetting layer quantum dots — •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 quantum communication applications.

Quantum dots are created by molecular-beam-epitaxy (MBE) in Stranski-Krastanov growth. InAs is deposited epitaxially onto GaAs and grows without relaxation to up to 1.5 monolayers of InAs. This layer is called the wetting layer, on top of which the self-organized quantum dots form.

We find, that a monolayer of AlAs 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)