Silver-coated inverse opals formed from polystyrene spheres for surface-enhanced Raman scattering

We have developed a new substrate for surface-enhanced Raman scattering (SERS) measurements involving a thin silver layer deposited over an ion-etched TiO₂ inverse opal. The latter is formed by chemically infiltrating a polystyrene opal array with TiO₂ followed by a thermal decomposition of the spheres. The SERS response of the these substrates is examined for several sphere sizes and lasers wavelengths; the results show that such substrates yield high enhance factors, comparable to substrates involving a silver layer deposited directly on a polystyrene opal array.