ABSTRACT
Abstract. We have studies magneto-optical properties of self-assembled quantum dot (QD) structures involving diluted magnetic semiconductors (DMSs) in various geometries. The observation of lower PL energy and smaller Zeeman shift in multi-layer QD system than in single layer QD structure suggests that there exists electronic coupling between the QD layers in multi-layer geometry. The double layer QD structure consisting of CdSe QDs and CdMnSe QDs exhibits a striking decrease of the PL intensity as a function of B. This phenomenon occurs due to the carrier tunnelling between non-DMS QDs and DMS QDs. In polarizationselective PL measurement of asymmetric double layer QD structures consisting of CdSe QD and CdZnMnSe QD layers, a significant enhancement of the degree of <T~ circular polarization emitted by the non magnetic CdSe QDs is observed, as compared to that observed in CdSe QDs without the influence of neighboring CdZnMnSe QDs. This behavior can be understood in terms of antiferromagnetic interaction between carrier spins localized in pairs of CdSe and CdZnMnSe QDs that are electronically coupled.
