Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 9: Poster I
HL 9.89: Poster
Montag, 27. März 2006, 15:15–17:45, P3
Magneto-Optical Investigation of InGaAs Quantum Dot Spin-LEDs — •J. Fallert1, W. Löffler1,2, D. Tröndle1,2, C. Mauser1, M. Hetterich1,2, and H. Kalt1,2 — 1Universität Karlsruhe (TH), Karlsruhe, Germany — 2DFG Center for Functional Nanostructures (CFN), Karlsruhe, Germany
We investigate p-i-n diode structures in which electrons are spin-polarized using a semimagnetic n-ZnMnSe layer and then injected into InGaAs / GaAs quantum dots. Magneto-optical measurements show efficient electrical spin injection as indicated by a total circular polarization degree (CPD) of up to 30% in the electroluminescence signal. We observe that depending on the emitted photon energy of the quantum dots the spectrally resolved CPD varies from 0% to 75%. HRTEM micrographs have been used to determine the present quantum dot geometries. Numerical calculations of electron and hole states in these quantum dots give quantitative results for the distribution in number and energy of bound states, depending on size and indium concentration.