Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 7: Quantum dots: Optical properties I
HL 7.5: Vortrag
Montag, 23. März 2009, 14:45–15:00, BEY 118
Cavity-enhanced emission of single photons by electrically driven InGaAs/GaAs-Quantum dot based RC-LEDs — •Jan Amaru Töfflinger1, Erik Stock1, Anatol Lochmann1, Dieter Bimberg1, Askhat K. Bakarov2, Aleksandr I. Toropov2, Aleksandr K. Kalagin2, and Vladimir A. Haisler2 — 1Institut für Festkörperphysik, TU-Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — 2Institute of Semiconductor Physics, Lavrenteva avenue 13, 630090 Novosibirsk, Russia
In order to optimize single photon emitting devices we developed Resonant-Cavity LEDs (RC-LED). MBE was employed to grow quantum dot densities of about 108cm−2. Such devices are a key for the realization of quantum cryptography systems. A main feature of our RC-LEDs is a built-in AlGaO current aperture allowing us to electrically excite a single quantum dot at very low currents below 15 nA. A specially designed resonant cavity leads to increased external quantum efficiency due to an increase of the spontaneous emission rate by the Purcell effect and a controlled direction of emission. We were able to focus on our APD-detectors a photon rate of almost 109 photons/sec which is a factor 10 times higher compared to devices without a resonant cavity [1]. Photon-correlation measurements prove that indeed single photons are emitted by a single quantum dot at a wavelength of about 940nm. This work is partly funded by the SfB 787 and the NATO SfP 982735.
[1] A. Lochmann et al., Electron. Lett. 42, 774 (2006)