Exploiting the interaction between a semiconductor nanosphere and a thin metal film for nanoscale plasmonic devicesElectronic supplementary information (ESI) available. See DOI: 10.1039/c6nr06504j

• Main Authors: Li, H, Xu, Y, Xiang, J, Li, X. F, Zhang, C. Y, Tie, S. L, Lan, S
• Format: Journal Article
• Language: English
• Published: 17.11.2016
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c6nr06504j

The interaction of silicon (Si) nanospheres (NSs) with a thin metal film is investigated numerically and experimentally by characterizing their forward scattering properties. A sharp resonant mode and a zero-scattering dip are found to be introduced in the forward scattering spectrum of a Si NS by putting it on a 50-nm-thick gold film. It is revealed that the sharp resonant mode arises from a new magnetic dipole induced by the electric dipole and its mirror image while the zero-scattering dip originates from the destructive interference between the new magnetic dipole and the original one together with its mirror image. A significant enhancement in both electric and magnetic fields is achieved at the contact point between the Si NS and the metal film. More interestingly, the use of a thin silver film can lead to vivid scattering light with different color indices. It is demonstrated that a small change in the surrounding environment of Si NSs results in the broadening of the resonant mode and the disappearance of the zero-scattering dip. Our findings indicate that dielectric-metal hybrid systems composed of semiconductor NSs and thin metal films act as attractive platforms on which novel nanoscale plasmonic devices can be realized. The interaction between a semiconductor nanosphere and a metal film can create a sharp resonant mode with a significantly enhanced field.