Spin-polarization dynamics in electrically excited single InGaAs quantum dots
Pablo Asshoff; Michael Hetterich; Jochen Zimmer; Heiko Füser; Wolfgang Löffler; Heinz Kalt; Pablo Asshoff; Institut für Angewandte Physik, Universität Karlsruhe (TH) and DFG Center for Functional Nanostructures (CFN), 76131 Karlsruhe, Germany; Michael Hetterich; Institut für Angewandte Physik, Universität Karlsruhe (TH) and DFG Center for Functional Nanostructures (CFN), 76131 Karlsruhe, Germany; Jochen Zimmer; Institut für Angewandte Physik, Universität Karlsruhe (TH) and DFG Center for Functional Nanostructures (CFN), 76131 Karlsruhe, Germany; Heiko Füser; Institut für Angewandte Physik, Universität Karlsruhe (TH) and DFG Center for Functional Nanostructures (CFN), 76131 Karlsruhe, Germany; Wolfgang Löffler; Institut für Angewandte Physik, Universität Karlsruhe (TH) and DFG Center for Functional Nanostructures (CFN), 76131 Karlsruhe, Germany; Heinz Kalt; Institut für Angewandte Physik, Universität Karlsruhe (TH) and DFG Center for Functional Nanostructures (CFN), 76131 Karlsruhe, Germany
Журнал:
Journal of Physics: Conference Series
Дата:
2010-01-01
Аннотация:
Potential applications of semiconductor quantum dots include spin memory and quantum information processing devices. For these, a rapid spin-initialization process would be desirable. In this contribution, we demonstrate nanosecond-pulsed electrical spin-injection into quantum dots embedded in a spin light-emitting diode. As inferred from time-resolved electroluminescence experiments, the circular polarization degree of the emitted light exhibits a peak at the beginning of the electroluminescence signal, indicating that the spin-initialization is more efficient in pulsed operation than under constant-current excitation. Results for the quantum-dot ensemble, the wetting layer states, and for single quantum dots are presented. We attribute these observations to energy-dependent spin-relaxation processes in the device.
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