Fabrication and characterization of coupled ensembles of epitaxial quantum dots and metal nanoparticles supporting localized surface plasmons

A stack of five layers of epitaxial InAs QDs with GaAs barriers was grown by molecular-beam epitaxy. The upper layer of QDs was capped by 3nm-GaAs/3nm-AlAs/4nm-GaAs layer sequence. Then, a thin silver layer was added via physical vapor deposition. After annealing isolated silver nanoparticles were formed above the layer of buried InAs quantum dots. We studied interplay of the exciton resonance in InAs QDs and plasmon resonance in Ag nanoparticles. In particular, we observed more than twofold enhancement of the exciton photoluminescence intensity from the InAs QDs when they were coupled to the silver nanoparticles.