Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 44: Quantenpunkte und -dr
ähte: Optische Eigenschaften III

HL 44.6: Talk

Thursday, March 27, 2003, 15:45–16:00, BEY/118

Light and Heavy Hole Contribution in Stacked Quantum Dots — •Andrei Schliwa, Robert Heitz, Sebastian Bognar, and Dieter Bimberg — Institut für Festkörperphysik, Technische Universität Institut für Festkörperphysik, Technische Universität Berlin

Recent polarisation measurements on columnar shaped InAs/GaAs quantum dots (QDs) [1] show a strong polarisation anisotropy, dependent on the number of stacked quantum dot layers. In a single layer structure the TE mode dominates whereas in stacks containing multiple QDs the intensitiy of the TM mode overtakes those of the TE mode [1].

We attribute this polarisation behavior to the light hole / heavy hole ratio of the hole wavefunctions, mainly determined by the biaxial strain inside the QD. We show, that the sign of the latter changes with an increasing number of QDs in the stack. Based on the eight-band-k·p model for QDs, we compare the energy levels and the evolution of the polarisation absorption spectra for stacks with an increasing number of InAs/GaAs QDs.

[1] Kita T., Wada O., Ebe H., Nakata Y., and Sugawara M., No-dqPolarization Controlled Edge Emission from columnar shaped InAs/GaAs self-assembled quantum dots,No-dq 2nd International Conference on Semiconductor QD, 2002