抄録
Structure of the Ag and Au dot dimers arrayed on a glass substrate was optimized to exhibit intense surface-enhanced Raman scattering (SERS) of adsorbed 4,4'bipyridine molecule in an aqueous solution. The substrates with the Ag and Au dimers show clear optical anisotropy correlated to the polarization direction of the array. The SERS intensity also showed the same polarization anisotropy, suggesting that the gap of the dimer induced intense SERS. Empirical enhancement factor of the present system was estimated to be between 10^5 and 10^9. The SERS activity of the Au dimer was kept even under intense light irradiation, while the structure of the Ag dimer was damaged under the similar conditions. Localization of the SERS active site was shown by Raman imaging measurement. Polarization dependence of the SERS image proves that the uniformity of the structure of the Ag and Au dimer array showing intense SERS.
