Surface-Enhanced Raman Scattering of Indigo on a Stable Silver Foil Substrate Prepared by a Nitric Acid Etching Method

A chemical etching method with HNO3-prepared silver foils was used for a Raman study. These foils were found to exhibit a strong SERS effect. An SEM image clearly shows that spherical particles exist in an oxidized state, with diameters in the range of 200 nm for oxidized silver. SERS spectrum of Indigo was taken to illustrate the usefulness of this sample preparation technique. HNO3-roughened silver foils seemed to be more easily prepared substrate systems for SERS studies. There is a high potential that this technique can be used in studies concerning the adsorption, molecular orientation, surface reaction, and surface catalysis at room or elevated temperatures.