Magneto-optical properties of non-magnetic semiconductor quantum dot and magnetic quantum well coupled structures

The magneto-optical properties of quantum-dot (QD) and quantum-well (QW) coupled structures are investigated using magneto-photoluminescence (PL). The coupled system consists of a self-assembled non-magnetic CdSe quantum-dot layer and a 7-nm ZnCdMnSe diluted-magnetic-semiconductor (DMS) quantum well (QW) layer. We have observed two well-separated PL peaks, one corresponding to emission from the CdSe QD layer and the other to the emission for ZnCdMnSe QW layer. The temperature dependence of the PL intensity clearly demonstrates the characteristics of zero- and two-dimensional structures for the CdSe QDs and the ZnCdMnSe QW, respectively. The significant PL energy shift and intensity variation observed for the DMS QW in a magnetic field can be understood based on the giant Zeeman splitting of the band edges of the DMSs. Furthermore, we have observed a type-II transition between the conduction band of the DMS QW and the valence band of non-DMS QD, which enables us to determine the band alignment of the coupled systems.