Periodically Varying Height in Metal Nano-pillars for Enhanced Generation of Localized Surface Plasmon Field

Localized surface plasmon resonance (LSPR) field condition study in metal nanostructure is important for different fields of applications which include chemical and bio-sensing investigations and in surface-enhanced Raman scattering (SERS)-based sensing investigations. Generally, sharp metal nano-tips, metal nano-colloids, nano-pillars and other sharp structures were used to generate different magnitudes of enhanced LSPR conditions, and all such structures usually provide tightly bound LSPR field conditions. In this paper, we demonstrate that with periodically varying height in metal nano-pillars, enhanced LSPR field condition can also be obtained and the enhancement scale of the generated field are found to be more than that of the uniformly structured metal nano-pillars. Different parameters which govern the enhancement factor for LSPR field condition have been thoroughly studied here. Since, periodic pattern of nano-pillars can be fabricated using lithographic tool such as e-beam lithography or focus-ion beam lithography, we envision that our simulation results would be useful in getting desired structure of the proposed nano-pillars for which it provides enhanced LSPR field condition as compared to uniformly structured metal nano-pillars.