ABSTRACT
We report time-resolved photoluminescence (PL) measurements of type-II GaSb/GaAs self-assembled quantum dots (QDs). The carrier dynamics of the QDs and the wetting layer were clearly observed. The QDs had the initial decay of ~23 ns, which was considerably longer than that for t.ype-I QDs. The radiative lifetimes strongly depend on excitation powers. This is attributed to spatially indirect excitons in a staggered (type-II) band alignment. In adition, we discuss a conduction band discontinuty of the QDs using the experiment results. The result indicated the conduction band discontinuity to be ~50 meV.
