Plasmonic properties of spheroid silicon-silver nanoshells in prolate and oblate forms

Abstract

Metal nanoparticles are excellent absorbers or scatterers of electromagnetic radiation, depending on their shape, size, material and refractive index of the surrounding medium. In studying the effect of shape, metallic core shell nanoparticle nanoparticles recently have attracted a great amount of interest in plasmonics due to the wide tunability of the plasmon resonances. In this paper, we have investigated the plasmonic properties of spheroid Silver-Silicon core shell nanoparticles, such as extinction, absorption and scattering cross sections and field enhancement factor as a function of parameters as: angle, wavelength and distance from the center. It has been shown that the localized surface plasmon resonance wavelength of these nanoparticles is severely dependent on shell thickness. The resonance wavelength of oblate core shell nanoparticle has a red shift relative to the prolate one. In both oblate and prolate core shell nanoparticles, field enhancement factor is extremely dependent on the shell thickness and in oblate core shell nanoparticle it’s dramatically greater than the prolate one in all distances from the center for all wavelengths and in both shapes, the maximum value of field enhancement factor take places in straight directions to applied field.