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HL: Fachverband Halbleiterphysik

HL 7: Quantum dots: Optical properties I

HL 7.4: Vortrag

Montag, 23. März 2009, 14:15–14:30, BEY 118

Microphotoluminescence on in situ stressed single InAs quantum dots — •Sven Wildfang, Matthias Klingbeil, Matthias Grave, Andrea Stemmann, Christian Heyn, Wolfgang Hansen, Detlef Heitmann, and Stefan Mendach — Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg

We have set up an experiment that enables us to vary and control the strain state of self-assembled InAs quantum dots (QDs) utilizing a micro mechanical device. We monitor the energy spectrum of a single QD by means of microphotoluminescence. When applying stress to a QD we find a reversible change in the spectrum. The distributions of stress in our structure during the experiments were simulated with COMSOL Multiphysics. The simulations were based on the works of van de Walle [1]. We simulated the behavior of the global band gap of InAs embedded in GaAs under stress induction. The results of our simulations could in principle be verified. Additionally in high resolution measurements we observe a change in the relative energy spacing both in the s- and the p-shell transitions. This arises from a change of the shape of the confining potential of a QD. [2, 3, 4]

We acknowledge financial support by the Deutsche Forschungsgemeinschaft via GrK 1286 and SFB 508.

[1] C. G. Van de Walle, Phys. Rev. B 39, 1871 (1989).

[2] A. Schliwa et al., Phys. Rev. B 76, 205324 (2007).

[3] M. Grundmann et al., Phys. Rev. B 52, 11969 (1995).

[4] S. Mendach et al., Phys. Rev. B 78, 035317 (2008).