Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties
HL 91.13: Poster
Thursday, March 14, 2013, 16:00–20:00, Poster A
Shape dependence of excitonic states in self-assembled GaAs/AlGaAs quantum dots — •Andreas Graf1, David Sonnenberg1, Andrei Schliwa2, Christian Heyn1, and Wolfgang Hansen1 — 1Institut für Angewandte Physik, Universität Hamburg, 20355 Hamburg, Germany — 2Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin, Germany
Local droplet etching (LDE) allows for a molecular beam epitaxy compatible self-assembled patterning of semiconductor surfaces.
Using LDE with aluminum droplets, nanoholes with a defined depth up to 100 nm are drilled in AlGaAs surfaces.
With the arsenic flux and the temperature during the LDE the shape, depth and density of the nanoholes are controlled [1].
Partial filling of the nanoholes with GaAs provides highly uniform strain-free quantum dots (QD).
Their shape is defined by the nanohole profile and the GaAs-filling level [2].
We study the QD shape dependence of the excitonic states with single-dot photoluminescence spectroscopy and compare the results with calculated transition energies.
For the calculation, a basis of single-particle wave functions is determined with k·p theory, and configuration interaction is used to determine excitonic states [3].
[1] Sonnenberg et al., APL 101, 143106 (2012)
[2] Heyn et al., APL 94, 183113 (2009)
[3] Schliwa et al., PRB 76, 205324 (2007)