Effects of substrate and polarization on plasmon driven surface catalysis in nanowire-film hybrid system

Plasmon driven surface catalysis (PDSC) reaction as an important and interesting surface plasmon related phenomenon has great significance in surface enhanced Raman scattering (SERS). In this work, the effects of substrate and polarization on PDSC reaction were investigated in the nanowire-film hybrid system. The different SERS spectra of 4-nitrobenzenethiol (4NBT) molecule in Ag nanowire-Au film and Ag nanowire-dielectric film hybrid system pointed out the PDSC reactions were greatly affected by substrate and the coupling efficiency of light to surface plasmon. These selective PDSC reactions were further analyzed and confirmed by the electric field distribution through Finite Difference Time Domain (FDTD) method. Furthermore, the data demonstrate the molecule conversion of PDSC plays an important role in the polarization dependence of analyte's SERS spectra. Our results not only enlarge the studies of PDSC reaction but also provide a useful view on spectrum analysis that molecule conversion of PDSC should be considered in SERS under some special situation.