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HL: Fachverband Halbleiterphysik
HL 31: Quantum dots and wires: Optical properties III
HL 31.3: Talk
Wednesday, March 28, 2007, 15:15–15:30, H17
Switch-on process of an electrically pumped singlequantum dot — •Erik Stock1, Anatol Lochmann1, Till Warming1, Dieter Bimberg1, Vladimir A. Haisler2, A. I. Toropov2, A.K. Bakarov2, and A.K. Kalagin2 — 1Technische Universität Berlin, Institut fürFestkörperphysik, Sekr. PN 5-2, Hardenbergstr. 36, 10623 Berlin,Germany — 2Institute of Semiconductor Physics,Lavrenteva avenue 13, 630090 Novosibirsk, Russia
Self-organized single quantum dots (QD) are of great interest for the realization of single-photon sources. One of the main features is the possibility to generate entangled photons, which can be achieved by exciton and biexciton emission of a single QD with a fine structure splitting less then the homogeneous broadening.
We demonstrate electrically pumped single InAs/GaAs QD emission in a pin-diode with submicron oxide current aperture. This QD-LED allows pumping of just one single QD. Via the pump current exciton and biexciton emission can be controlled as required for entangled photons sources. In highly resolved spectra we observe the switch-on of the electroluminescence: First a single emission lines becomes visible. With increasing current this emission shifts towards higher energy and splits into up to three emission lines separated by ∼ 70 µeV. At higher current they rejoin to form a single unpolarized emission line and stay on a fixed emission energy. This splitting of emission may influence the entanglement of emitted photon pairs and has to be considered for the development of electrically driven single photon sources.