摘要
Silver surfaces producing enhancement of the Raman scattering for adsorbed molecules have been simply prepared by etching them in HNO<sub>3</sub> solution. The dependence of the enhancement on etching time at different concentrations of the etching solution has also been investigated. When etched with 2.5 mol/L HNO<sub>3</sub> for 10-20 min, silver surfaces can all produce strong enhancement, and the surface-enhanced Raman scattering （SERS） activity can survive for more than 10 h in air. For Kr<sup>+</sup> laser excitation at 647.1 nm, the observed
