Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 42: Quantum dots and wires: Preparation and characterization
HL 42.3: Vortrag
Donnerstag, 4. April 2019, 15:30–15:45, H34
Tuning the emission energy of 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 InxGa1−xAs quantum dots (QDs) were grown on GaAs(100) substrates by molecular beam epitaxy (MBE). The density can be controlled by modifying the growth conditions. 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. An alternative approach is the deposition of a subcritical amount of InAs with subsequent annealing. Using this approach, we were able to achieve a low density of 108 cm−2 homogeneously over the whole wafer. 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 InxGa1−xAs QDs we were able to increase the emission energy to 1.3 eV.
The QDs grown by different approaches have been investigated by photoluminescence spectroscopy and atomic force microscopy. The results are discussed in comparison.