Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 31: Poster I: Devices, Quantum Dots and Quantum Wires

HL 31.39: Poster

Tuesday, March 23, 2010, 18:30–20:30, Poster D1

Electrical spin-injection into single InGaAs quantum dots: circular polarization degree of light from different excitonic complexes — Pablo Asshoff, •Gunter Wüst, Andreas Merz, Michael Hetterich, and Heinz Kalt — Karlsruhe Institute of Technology (KIT) and DFG Center for Functional Nanostructures (CFN), 76131 Karlsruhe, Germany

Quantum dots embedded in spin light-emitting diodes (spin-LEDs) can be charged with spin-polarized electrons and unpolarized holes. The subsequent radiative recombination leads to a circular polarization of the emitted light, revealing the excitonic spin state inside the quantum dot. Spin-injection efficiencies are very high for individual quantum dots [1]. Pulsed electrical injection shines light on the temporal evolution of the spin polarization [2]. Here, we compare the power-dependent behavior of single quantum dot emission lines due to recombination of different excitonic complexes, when optical and electrical pumping are used, respectively. This allows for measuring the circular polarization degree related to different excitonic species during all-electrical spin-injection.

[1] M. Hetterich et al., in Advances in Solid State Physics, edited by R. Haug (Springer, Berlin, 2009), Vol. 48, p. 103; [2] P. Asshoff et al., Appl. Phys. Lett. 95, 202105 (2009)