Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.89: Poster
Donnerstag, 17. März 2011, 18:00–21:00, P4
Optical properties of GaAs quantum dots fabricated by filling of self-assembled nanoholes — •Andreas Graf1, David Sonnenberg1, Christian Heyn1, Andrei Schliwa2, 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) is a technique to fabricate self-assembled patterning of semiconductor surfaces. Using LDE, we drill nanoholes (depth ≥ 7 nm) with Al droplets on the AlGaAs substrate and partially fill these with GaAs. This results in strain-free GaAs quantum dots (QDs) [1]. By control of the filling level a very narrow size distribution is achieved within the QD ensemble. We study photoluminescence spectra of QD ensembles as well as of single QDs and discuss the observations in view of QD size dependence, the shell structure, and the excited states in the QDs. In particular, the fine-structure splitting of neutral exciton and biexciton peaks of single QDs is studied. Furthermore, a model using the eight-band k·p theory and configuration interaction [2] is used to interpret the experimental results.
[1] Heyn et al., Appl. Phys. Let. 94, 183113 (2009)
[2] Schliwa et al., Phys. Rev. B 80, 161307 (2009)