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HL: Fachverband Halbleiterphysik
HL 7: Quantum dots: Optical properties I
HL 7.2: Talk
Monday, March 23, 2009, 13:45–14:00, BEY 118
InGaAs QDs on GaAs(111) substrate for entangled photon pairs — •Irina Ostapenko1, Andrei Schliwa1, Erik Stock1, Sven Rodt1, Vladimir Haisler2, and Dieter Bimberg1 — 1IFP, TU Berlin — 2Institute of Semiconductor Physics, Novosibirsk, Russia
Quantum dots (QDs) are ideally suited for the generation of polarization-entangled photon pairs [1] that enable certain quantum cryptography protocols [2] and quantum teleportation [3]. However, even a small fine-structure splitting of the bright-exciton state may hinder the formation of such pairs based on the biexciton to exciton to vacuum recombination cascade. Our recent calculations [4] have revealed that growth of InGaAs QDs on GaAs(111) substrates leads to a vanishing fine-structure splitting. Here we expect a three-fold rotational symmetry in the growth plane and piezoelectric effects will not reduce the symmetry of the confining potential in contrast to QDs grown on GaAs(001) substrates [5]. We report on a successful approach to grow such QDs via droplet-mode MBE. Optical characterization is performed by cathodoluminescence and electroluminescence in combination with metal shadow masks. The results are compared to droplet-exiptaxy QDs on "standard" GaAs(001) substrates.
[1] O. Benson et al., Phys. Rev. Lett. 84, 2513 (2000)
[2] A. K. Ekert, Phys. Rev. Lett. 67, 661 (1991)
[3] T. Jennewein et al.,Phys. Rev. Lett. 88, 017903 (2002)
[4] A.Schliwa et al., Deutsche Patentanmeldung (2008)
[5] O.Stier et al., Phys. Rev. B 59, 8 (1999)