Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 55: Quantum dots and wires: Preparation and characterization

HL 55.6: Talk

Friday, March 16, 2018, 10:45–11:00, A 151

Self-assembled low density In(Ga)As quantum dots — •Timo Langer, Nandlal Sharma, and Dirk Reuter — Universität Paderborn, Department Physik, Warburger Str. 100, 33098 Paderborn

Self-assembled InAs and In_xGa_1−xAs quantum dots (QDs) were grown on GaAs (100) substrates by molecular beam epitaxy (MBE). By modifying the growth conditions, it is possible to control the density. Furthermore, the transition energies can be tuned by using the In-flush-technique or by ex-situ annealing.

Experiments using a gradient approach resulted in densities from 10⁸ to 10¹⁰ cm⁻². The ground state transition energy at 4.2 K can be increased from 1.0 to 1.3 eV by using the In-flush-technique. Also by growing In_xGa_1−xAs QDs we were able to achieve emission energies around 1.3 eV. The QDs have been analyzed by photoluminescence spectroscopy, atomic force microscopy and capacitance-voltage-spectroscopy. We will also discuss an alternative approach to realize low QD densities employing a subcritical InAs deposition and subsequent annealing.