Excitation of Surface Plasmon Resonance in Composite Structures Based on Single-Layer Superaligned Carbon Nanotube Films

Abstract

Surface-enhanced Raman scattering (SERS) provides valuable information on the vibrational modes of molecules and the physical mechanism of surface plasmon resonance (SPR). In this paper we study the localized SPR process in Ag- or Ag/oxide-coated single-layer superaligned carbon nanotube (SACNT) films. Because of the unidirectional alignment of the carbon nanotubes in these films, the Raman signal is higher when the laser is polarized parallel to the aligned direction than when perpendicular to it. We investigated the polarization-dependent transmittance and Raman spectra for various Ag particle sizes and different oxide medium layers to study the localized SPR in these composite structures. These results systematically characterize the properties of SACNT film-based SERS substrates and clarify the origin of transmittance peaks