Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


J. Korean Phy. Soc. 2009; 55(1): 76-79

Published online July 15, 2009

Copyright © The Korean Physical Society.

Spin Phenomena of CdZnSe Self-assembled Quantum Dots Investigatedby Magneto-photoluminescence

Yungjun Kim, Sanghoon Lee, M. Dobrowolska, J.K. Furdyna


Magneto-photoluminescence (PL) experiments were carried out on aself-assembled CdZnSe/ZnSe quantum dot (QD) system. The intensitiesof the PL peak exhibited significant differences for the twocircular polarizations when a magnetic field was applied. A simpletwo-level rate equation model, including the spin flip time $ au_s$and the exciton recombination time $ au_r$ , was used to analyzethe observed degree of the polarization in the polarizationselective PL measurements. Specifically, the magnetic fielddependence of the polarization was fitted by treating$ au_s/ au_r$ as a fitting parameter in the model. The bestfitting was obtained with the value of $ au_s/ au_r sim sigma$,indicating that the spin relaxation time is much longer than theexciton recombination time. Such polarization selective PLmeasurements were further performed at several differenttemperatures, which showed a systematic decrease in the degree ofpolarization with increasing temperature.

Keywords: Self-assembled quantum dot, Spin relaxation, Polarization