Raman and DFT study of the reaction of hydrazine and hypophosphite on a Cu surface in the electroless deposition process

Oxidation of the reductants is a dominant factor in the electroless deposition process. In order to obtain fundamental knowledge about the reaction mechanism of reductant oxidation for more precise control of the solid-liquid interface in this process, we have attempted to characterize the behavior of reductants adsorbed on Cu surface by using plasmon antenna enhanced Raman scattering. The concentric-patterned antenna coated with Cu, which consisted of a dimple array with single hole or a single hole with coaxial dimples, was designed by Finite Difference Time Domain (FDTD) calculation to enhance the electric field by focusing surface plasmons. By using this antenna and comparing the spectra to the results of Density Functional Theory (DFT) calculations, Raman peaks of adsorbed reductants on Cu were identified. Furthermore, we examined the conformation of adsorbed reductants by DFT calculation of the adsorption model of reductants on fcc-Cu(111) surface. As a result, the nature of reductant adsorption on Cu surface has been investigated from a computational point of view and an experimental point of view, and such in-situ characterization will be useful for analysis of a variety of systems at solid-liquid interface.