Enhanced Raman Scattering of ZnO Quantum Dots on Silver Colloids

Enhancement of the Raman signals of ZnO quantum dots on Ag colloids was studied. Unique ZnO/Ag nanostructure materials were obtained by self-assembly of Ag nanocrystals using ZnO nanoparticles as seeds. The morphology and optical properties of ZnO/Ag core/shell particles are dependent on the quality of deposited Ag. The surface plasmon absorption band of Ag shifts toward lower energy due to the interaction between Ag and ZnO quantum dots. The intensities and orders of multiphonon fingerprint Raman lines of ZnO nanocrystals were increased remarkably from the effect of Ag. The efficient quantum dot excitation within the locally enhanced electromagnetic field produced by the silver nanoparticles is evidenced by the observation of the surface plasmon resonance in the enhanced Raman of ZnO nanocrystals.

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