Regensburg 2022 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 17: Quantum Dots and Wires 4: Devices

HL 17.6: Talk

Wednesday, September 7, 2022, 11:15–11:30, H32

GaSb quantum dots surrounded by AlGaSb with indirect-direct bandgap crossover at telecom range — •Lucie Leguay and Andrei Schliwa — Institut für Festkörperphysik, Technische Universität Berlin

We report the modeling and theoretical characterization of a new type-I semiconductor material based on GaSb quantum dots embedded into AlGaSb with GaSb as substrate. The calculations are performed by the nextnano++ solver, using both the effective mass and the 8-band k·p method.

Experimental work shows the formation of nano-holes with a wide range of tunability in depth and density by the local droplet etching of a surface of AlGaSb by liquid gallium [1]. Then, optically active quantum dots are obtained by filling those nano-holes with GaSb and by the deposition of a GaSb quantum well on top [2].

Our calculations demonstrate an indirect-direct bandgap crossover as the thickness of the quantum well increases, which allows control of the system’s luminescence. In the direct bandgap regime, the quantum dots emit narrow excitonic spectral lines in the telecom wavelength range. These properties, as well as the low density of the quantum dots, show a lot of promise for applications in the field of infrared quantum optics.

[1] J. Hilska, A. Chellu, T. Hakkarainen, Cryst. Growth Des. 2021, 21, 1917-1923

[2] A. Chellu, J. Hilska, J-P Penttinen, T. Hakkarainen, APL Mater. 9, 051116 (2021)