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HL: Halbleiterphysik
HL 41: Heterostructures
HL 41.2: Vortrag
Donnerstag, 30. März 2006, 11:15–11:30, BEY 154
Electrical Spin Injection from ZnMnSe into InGaAs/GaAs Quantum Dots — •W. Löffler1,2, D. Tröndle1,2, J. Fallert1, H. Kalt1,2, D. Litvinov3,2, D. Gerthsen3,2, J. Lupaca-Schomber1,2, T. Passow1,2, B. Daniel1,2, J. Kvietkova1, and M. Hetterich1,2 — 1Institut für Angewandte Physik, Universität Karlsruhe (TH), D-76128 Karlsruhe (Germany) — 2DFG Center for Functional Nanostructures (CFN), Universität Karlsruhe (TH), D-76128 Karlsruhe (Germany) — 3Laboratorium für Elektronenmikroskopie, Universität Karlsruhe (TH), D-76128 Karlsruhe (Germany)
We report on efficient injection of spin-polarized electrons into InGaAs quantum dots (QDs) embedded in a p-i-n light-emitting diode structure. For electron spin alignment we made use of a semi-magnetic spin-aligner layer (ZnMnSe) on top. The spin-LEDs have been grown by molecular-beam epitaxy and show a nearly perfect III-V/II-VI interface in transmission electron microscopy. In an external magnetic field, we find a circular polarization degree of up to 75% for the electro-luminescence of the QDs. We can clearly attribute this polarization degree to be due to recombination of spin-injected electrons (with unpolarized holes) by comparison with results from reference devices without spin aligner and all-optical measurements. The robustness of this injection scheme is characterized with respect to sample temperature and current density. From that, we deduce that this combination of nearly perfect spin-alignment in ZnMnSe and ultra-long spin lifetimes in InGaAs/GaAs QDs is a very promising candidate for spintronics applications.