Anomalous temperature dependence of the carrier capture time into InAs/GaAs quantum dots grown on a quantum wire array

Carrier capture into quantum dots (QDs) grown on top of a 16 period quantum wire (QWR)-superlattice is studied as a function of temperature. Time-resolved differential reflectivity reveals an anomalous increase of the capture time between 40 and 100 K. Photoluminescence data indicate carrier re-emission out of the QWRs into the QDs, in this temperature range. The anomalous temperature dependence is interpreted as due to the temperature dependence of the effective carrier diffusion length in this structure.