High-field magneto-optical study of localized excitons in CdTe/Cd1−xMnxTe multiple quantum wells

Abstract The photoluminescence (PL) spectra of CdTe/Cd 1− x Mn x Te multiple quantum wells (MQW) were measured in pulsed magnetic fields up to 40T. The samples were grown on GaAs(1 0 0) substrates at 320°C (lower- T s sample) and 360°C (higher- T s sample) by the molecular beam epitaxy (MBE) method. In the magnetic field dependence of the PL peak positions, both red and blue shifts were observed in the low- and high-magnetic-field regions, respectively. The former is interpreted as a large Zeeman effect caused by the penetration of the exciton wavefunction of the CdTe quantum well layer into the Cd 1− x Mn x Te barrier layer. The latter is due to a diamagnetic shift of excitons in the CdTe quantum well layer. In the case of the higher- T s samples, no diamagnetic shift and anomalously large Zeeman shift were observed. These facts suggest that excitons in the quantum well layer of higher- T s samples are localized at the heterointerfaces of CdTe/Cd 1− x Mn x Te. The origin of the localization is discussed.