Spin polarization of self-assembled CdSe quantum dots in ZnMnSe

Abstract

Nearly complete spin polarization (SP) of carriers was observed in photoluminescence (PL) experiments on CdSe self-assembled quantum dots (QDs) embedded in ZnMnSe at 5 K in magnetic fields above 1 T. The redshift of the PL from CdSe QDs in the presence of the magnetic field was less than that of ZnMnSe, but still sufficiently large to account for the high SP. At low fields, however, the SP of carriers in CdSe QDs is observed to be smaller than in the surrounding ZnMnSe. This, along with time-resolved PL data, suggests that the SP in CdSe QDs is mainly due, not to the injection of SP carriers from ZnMnSe, but rather due to the Zeeman splitting of internal QD states.