EXCITON DYNAMICS AND HIGH-DENSITY EFFECTS IN ZNSE ZNMNSE QUANTUM STRUCTURES GROWN BY MOLECULAR-BEAM EPITAXY/

ZnSe well exciton features in ZnSe/ZnMnSe quantum structures grown by molecular beam epitaxy (MBE) are investigated using various spectrosco pic techniques. Steady-state photoluminescence and excitation spectros copy demonstrate an enhanced effective band offset due to tensile stra in and a confinement induced shift of the excitonic resonances up to 1 00 meV. Progressive localization of excitons on the 10 ps time scale f ollowed by rapid recombination within 100 ps is observed in time-resol ved luminescence. Transient pump-probe measurements show clear nonline ar excitonic absorption under 2 muJ/cm2 excitation with a recovery on the same time scale as the radiative recombination.