Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 24: Quantum Dots and Wires, Optical Properties II: Single Photon Sources

HL 24.2: Talk

Tuesday, March 23, 2010, 11:45–12:00, H17

Quantum-dot-based, electrically-driven single-photon sources with 1 GHz excitation rate and with site-controlled quantum dot — •Jan A. Töfflinger¹, Erik Stock¹, Anatol Lochmann¹, Waldemar Unrau¹, Dieter Bimberg¹, Askhat K. Bakarov², Aleksandr I. Toropov², Aleksandr K. Kalagin², Vladimir A. Haisler², Paola Atkinson³, and Oliver G. Schmidt⁴ — ¹Institut für Festkörperphysik, TU-Berlin, 10623 Berlin, Germany — ²Institute of Semiconductor Physics, 630090 Novosibirsk, Russia — ³MPI für Festkörperforschung, 70569 Stuttgart, Germany — ⁴IIN, IFW Dresden, 01069 Dresden, Germany

For future quantum cryptography systems the development of highly efficient, electrically pumped single-photon sources with high repetition rates is of utmost importance. We have developed InGaAs/GaAs-quantum dot (QD) based Resonant-Cavity LEDs (RC-LED). A built-in AlGaOx current aperture allows electrical excitation of a single QD. The resonant cavity leads to increased external quantum efficiency and due to the Purcell effect to an increase of the spontaneous emission rate allowing us to electrically pump the single QD at 1 GHz repetition rate. To further optimize our single photon sources and to increase the device yield we also demonstrate a new electrically pumped LED with a site-controlled MBE-grown InGaAs/GaAs-QD on pre-patterned GaAs substrate. Electroluminescence measurements show pure spectrum with only lines from a patterned QD and demonstrate single photon emission with a second order correlation function g²(0)≤0.4. This work is partly funded by SfB 787 and NATO SfP 982735.