Inhibited recombination of negatively-charged excitons in GaAs quantum wells at high magnetic fields

Abstract

We have studied time-resolved photoluminescence (PL) from negatively-charged excitons (X−) in GaAs quantum wells at high magnetic fields. The PL decay time of X− showed large increase in magnetic fields perpendicular to the well layers. This results from a reduction of coherence volume when the translational motion of charged X− is confined by cyclotron orbit. In contrast, no such increase was seen in parallel magnetic fields, since the motion of X− is not completely confined in this case. The inhibited recombination of X− is a remarkable manifestation of exciton coherence volume effect.