Optical properties of manganese-doped ZnSe/ZnS quantum dots grown by molecular beam epitaxy

Optical properties of Mn-doped ZnSe/ZnS quantum dots (QD's) have been investigated by both steady-state and time-resolved photoluminescence (PL) measurements. Strong photoluminescence associated with Mn intra-d shell transitions has been observed for QD's with a longitudinal thickness of just few monolayers (ML's). The PL decay involves two processes with different lifetimes of which the faster one has a lifetime of about 5 mu s which is almost independent of the well thickness, while the other process has a Lifetime varying from 40 to 80 mu s when the well width decreases from 6 to 0.25 ML. The experimental results are interpreted by the use of rate equations which suggests that the enhanced Mn emission might be due to the relatively enhanced energy transfer from the QD's to the Mn atoms.