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We study Ag nanopattern arrays formed using ferroelectric lithography based on two separate approaches, i.e., periodically poled lithium niobate (PPLN) and periodically proton exchanged (PPE) template methods. We demonstrate that such nanoarrays are plasmon active. Raman spectroscopy was applied to study molecular probe 4-aminothiophenol (4-ABT) absorbed onto a silver nanostructured array. The observed Raman spectra show peaks arising from b2modes, which occur for plasmon enhanced Raman from 4-ABT in place of a1modes, which occur in normal Raman scattering. We demonstrate that the PPLN and PPE substrates possess different plasmonic properties with PPE creating a stronger SERS signal relative to PPLN substrates.

Photodeposition of metallic nanostructures onto ferroelectric surfaces is typically based on patterning local surface reactivity viaelectric field poling. Here, we demonstrate metal deposition onto substrates which have been chemically patterned viaproton exchange (i.e., without polarization reversal). The chemical patterning provides the ability to tailor the electrostatic fields near the surface of lithium niobate crystals, and these engineered fields are used to fabricate metallic nanostructures. The effect of the proton exchange process on the piezoelectric and electrostatic properties of the surface is characterized using voltage-modulated atomic force microscopy techniques, which, combined with modeling of the electric fields at the surface of the crystal, reveal that the deposition occurs preferentially along the boundary between ferroelectric and proton-exchanged regions. The metallic nanostructures have been further functionalized with a target probe molecule, 4-aminothiophenol, from which surface-enhanced Raman scattering (SERS) signal is detected, demonstrating the suitability of chemically patterned ferroelectrics as SERS-active templates.