Surface plasmon resonance enhanced band-edge emission of CdS–SiO2 core–shell nanowires with gold nanoparticles attached

Abstract

Inspired by the good match between the surface-plasmon energy of Au nanoparticles and the emitted photon energy of CdS nanowires, CdS–SiO₂ core–shell nanowires with Au nanoparticles attached (CdS–SiO₂–Au) were prepared to investigate the interaction between the semiconductor and the metal. Photoluminescent and lifetime measurement reveal that the band-edge emission of CdS nanowires in this hybrid structure has a fivefold enhancement compared with pure CdS nanowires due to the surface plasmon resonance. In addition, the existence of an optimized thickness of the SiO₂ layer for the emission enhancement indicates that the interactions between the metal and the semiconductor occur constructively only at appropriate distances. These CdS–SiO₂–Au nanowires with tailored morphologies and enhanced band-edge emission have potential applications in solar cells, photodetectors and bio-nanotechnology.