MAGNETOOPTICAL STUDY OF ZNSE (ZN,MN)SE AND ZNSE/(ZN,CD,MN)SE QUANTUM-WELL STRUCTURES AND SUPERLATTICES/

Quantum well structures with semimagnetic barriers, ZnSe/(Zn,Mn)Se, or semimagnetic wells, (Zn,Cd,Mn)Se/ZnSe, are studied by luminescence an d reflection spectroscopy in an external magnetic field up to 7.5 T. A unique offset dependence on the manganese concentration and a type co nversion of the ZnSe/(Zn,Mn)Se heterostructures due to the giant Zeema n splitting of the barriers are found. In the (Zn,Cd,Mn)Se/ZnSe struct ures, a strong reduced energy transfer from the exciton states to the Mn internal transition was found, which is further suppressed by an in creasing magnetic field. Therefore (Zn,Cd,Mn)Se quantum wells can be p roposed to be suitable and effective for tuneable blue-green laser dev ices in an external magnetic field. The field dependent energy splitti ng both of well and barrier excitons are significantly anisotropic wit h respect to the orientation of the magnetic field B parallel or perpe ndicular to the growth axis. This magneto-optical anisotropy can be ex plained by the mixing of the heavy and light hole states in the framew ork of a multi-band envelope-function approximation.