Surface Plasmon Resonance Study of Au Nanorod Structures Templated in Mesoporous Silicon

Au nanorods forming carpet-like structures have been fabricated by electrochemical methods in mesoporous silicon templates. The anodically grown monodisperse pores on Si (100) were used to cathodically grow the Au structures from complexated Au solutions. Such structures feature selective absorption of light in the visible/near infrared wavelength range that can be tuned by controlling the aspect ratio and dielectric surrounding media. In the present work, the visible light absorption of Au structures has been studied and correlated with the light absorption of ideal structures with increasing complexity. According to these simulations, the observed selective light absorption arises from the anisotropic surface plasmon resonance (SPR) of the rods and a secondary SPR of isolated Au nanoparticles adsorbed on the rods.