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Exciton dynamics has been studied in quantum wells, quantum dots and quantum wires of diluted magnetic semiconductors by time-resolved photoluminescence spectroscopy. The transient exciton photoluminescence with resonant excitation in Cd 1− x Mn x Te/ZnTe ( x =0.1) multiple quantum wells shows the formation of magnetic polarons in the quantum well excitons. Free and localized states of the excitonic magnetic polarons are distinguished from the difference of the lifetimes and the binding energies. The magnetic polaron formation accompanied with emission or absorption of LO phonons was also observed. Quantum dots of Cd 1− x Mn x Se grown by the self-organization mode showed the luminescence of confined excitons in the dots. The Mn ions in the quantum dots induce large Zeeman shifts and the excitonic magnetic polaron formation in the dots. Quantum wires of Cd 1− x Mn x Se showed polarized exciton emissions parallel to the wires. The polarization was decreased by the external magnetic field perpendicular to the wires. The excitonic magnetic polaron states in the quantum wires are also discussed.

Time-resolved photoluminescence (PL) and optical pump–probe experiments were carried out in Cd1−xMnxTe/ZnTe multiple quantum wells to study the dynamics of the exciton magnetic polaron in this material. In the pump–probe data, three signals were detected. The main signal is negative and monitors the energy relaxation of the excitons created by the pump pulse. The other two pump–probe signals are positive and their intensity grows while the excitons created by the pump pulse recombine. The low-energy positive pump–probe signal is found to track the average Mn spin polarization in the sample. On the contrary, the high-energy positive peak indicates the enhancement of the density of states due to correlation effects.

Exciton localization is studied with time-resolved photoluminescence (PL) in Cd 1− x Mg x Te epilayers. The energy relaxation rate of excitons is found to be energy dependent and reduces drastically below an effective excitonic mobility edge. This particular property results in the saturation of the PL intensity rise time below the mobility edge and a two-exponential decay for the PL intensity and the energy relaxation of the excitons.

Luminescence of excitons has been studied in quantum nanostructures of Cd1−xMnxSe by time-resolved spectroscopy with femtosecond pulse lasers. Self-organized quantum dots show luminescence of quantum-confined excitons. Quantum wires show the exciton luminescence polarized parallel to the wires. Large Zeeman effects and the excitonic magnetic polaron formation are observed in these quantum structures.

The decay properties of excitons in Cd 1− x Mn x Te/Cd 1− y Mg y Te single and multiple quantum wells are investigated by the time-resolved photoluminescence measurements. We observed the conversion of the dark excitons to the bright excitons by a spin-flip process. This yields a two-exponential decay of the photoluminescence intensity. The magnetic field dependence of the two-exponential decay is discussed in the frame of the spin-flip scattering and the giant Zeeman splitting in single quantum wells. The temperature dependence of exciton decays is interpreted by the increase of exciton scattering rate due to thermal activation in multiple quantum well.