The light emission enhancement behavior from single ZnO nanowires integrated with metallic contacts is investigated by micro-photoluminescence measurements.Apart from surface plasmon polaritons at the air/metal interface,the emission of a single ZnO nanowire can be coupled into guided modes of surface exciton-plasmon polaritons(SEPPs).The out-coupling avenues of SEPP guided modes are modeled in the presence of nanostructures,such as corrugation and gratings,on the metal surface.The guided modes of SEPPs in metal-contacted ZnO nanowires are calculated using the effective index method.The enhanced light emission from single semiconductor nanowires shows promise for use in highly efficient nano-emitters and nano-lasers,as well as macroscopic solid state light sources with very high efficiency.
Symmetric tapered dielectric structures in metal have demonstrated applications such as the nanofocusing of surface plasmon polaritons, as well as the waveguiding of V-channel polaritons. Yet the fabrication of smooth-surfaced tapered structure remains an obstacle to most researchers. We have successfully developed a handy method to fabricate metal-sandwiched tapered nanostructures simply with electron beam lithography. Though these structures are slightly different from conventional symmetric V-shaped structures, systematic simulations show that similar functionality of surface plasmon polariton nanofocusing can still be achieved. When parameters are properly selected, wavelength- selective nanofocusing of surface plasmon polaritons can be obtained.
