Propagation dynamics of exciton spins in a high-density semiconductor quantum dot system
2009 (English)Conference paper (Refereed)
We study propagation dynamics of exciton spins in a system composed of high-density self-assembled quantum dots (QDs) of CdSe and a diluted magnetic semiconductor (DMS) layer of ZnMnSe, where spin-polarized excitons are generated in the DMS layer and are subsequently injected into the QDs. The degree of circular polarization, P, of excitonic photoluminescence at 5 T in the coupled QDs shows a rapid increase with increasing delay time after a linearly polarized pulsed excitation, indicating the exciton-spin injection from the ZnMnSe to CdSe-QDs. The P value tends to decay gradually because of the exciton-spin relaxation in the QDs after the injection. The spin-polarized excitons in the QD ensemble migrate simultaneously from the QDs with higher exciton energies to those with lower exciton energies, where the exciton-spins relax inside each dot during the migration. Therefore, the observed P values in the QD emission band are affected by this feeding of the relaxed spins.
Place, publisher, year, edition, pages
phys. stat. sol. c , 2009. Vol. 6, no 1, 50-52 p.
Natural Sciences Condensed Matter Physics
IdentifiersURN: urn:nbn:se:liu:diva-18721DOI: 10.1002/pssc.200879875OAI: oai:DiVA.org:liu-18721DiVA: diva2:221251
8th International Conference on Excitonic Processes in Condensed Matter (Excon'08)