Fabrication of Si-Ag "wire-cap" nanostructures for metal-enhanced fluorescence

We demonstrate a convenient nanotechnique to modulate Si-Ag "wire-cap" nanostructures for metal-enhanced fluorescence by self-selective electroless plating on Si. Optimized coupling between Ag caps and organic emitter can be achieved by altering the bending degree of the Si nanowires resulting in significantly enhanced local electric field intensity. The enhanced photoluminescence from the organic emitter coupled Si-Ag "wire-cap" nanostructures derives from the excitation of localized surface plasmons between the Ag nanocaps and also the energy transfer effect in the surface plasmon resonant coupling between the organic emitter and Ag caps. Our technique has potential applications in biochemical sensors and light emitters.