POLARIZED PHOTOLUMINESCENCE OF EXCITONS IN n-, p- AND UNDOPED InAs/GaAs QUANTUM DOTS

Abstract

Polarized photoluminescence from InAs / GaAs self-assembled quantum dots has been investigated under continuous wave excitation by circularly polarized light. Depolarization of the photoluminescence in a magnetic field perpendicular to the wavevector of the exciting light (Hanle effect) was studied. For n-doped, undoped and p-doped quantum dots the observed Hanle curves exhibit qualitatively different shapes: single-, bi-, and tri-Lorentzian, respectively. In the two latter cases the complicated shape of the Hanle curve is attributed to the different processes of radiative recombination which take place simultaneously. Recombination of uncharged excitons and recombination of positively charged exciton complexes are considered. Corresponding spin lifetimes are determined.