Magneto-photoluminescence studies of AlInAs/AlGaAs self-assembled quantum dots with type-II band alignment

Magnetic-field dependence of the photoluminescence (PL) characteristic of type-II quantum dots (QDs) was observed in AlInAs/AlGaAs self-assembled QDs. Parameters of the exciton in this system such as a lateral confining energy, a reduced mass and an average radius estimated from the magnetic-field dependence clearly indicated that type-II excitons with holes confined in QDs and electrons in AlGaAs matrix were formed. The PL intensity change both in the Faraday and Voigt configurations, which was well-explained in terms of the shrinkage of electron and hole wave functions and resulting change of their overlap, indicated that electrons in AlGaAs matrix were bound at the top or the bottom of QDs where holes were trapped. The competition between the increased overlap of electron and hole wave functions and the transition of band alignments from type-l to type-II induced by high magnetic fields was also found to provide an anomalous magnetic field dependence of the PL intensity in a particular sample where many type-I QDs were included.