title: Strong Light Confinement in Metal-Coated Si Nanopillars: Interplay of Plasmonic Effects and Geometric Resonance.
abstract: We investigated the influence of metal coating on the optical characteristics of Si nanopillar (NP) arrays with and without thin metal layers coated on the sample surface. The reflection dips of the metal-coated arrays were much broader and more pronounced than those of the bare arrays. The coated metal layers consisted of two parts-the metal disks on the Si NP top and the holey metal backreflectors on the Si substrate. The Mie-like geometrical resonance in the NPs, the localized surface plasmons in the metal disks, and the propagation of surface plasmon polariton along the backreflector/substrate interface could contribute to the reflection spectra. Finite-difference time-domain simulation results showed that the interplay of the plasmonic effects and the geometric resonance gave rise to significantly enhanced light confinement and consequent local absorption in the metal-Si hybrid nanostructures.
authors.affiliation: Department of Physics, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Sujung
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Physics, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Eunah
authors.initials: E
authors.lastname: Kim
authors.affiliation: Department of Physics, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Yeon Ui
authors.initials: YU
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Eunkyo
authors.initials: E
authors.lastname: Ko
authors.affiliation: Device Platforms Lab., Device Engineering Labs., Korea Advanced Nano Fab Center (KANC), Suwon, 443-270, Korea.
authors.forename: Hyeong-Ho
authors.initials: HH
authors.lastname: Park
authors.affiliation: Department of Physics, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Jeong Weon
authors.initials: JW
authors.lastname: Wu
authors.affiliation: Department of Physics, Ewha Womans University, Seoul, 120-750, Korea. dwkim@ewha.ac.kr.
authors.forename: Dong-Wook
authors.initials: DW
authors.lastname: Kim
keywords: Localized surface plasmon; Mie resonance; Nanopillar array; Si; Surface plasmon polariton