Formation of cyanide compounds during preparation of gold surfaces evidenced by surface‐enhanced Raman spectroscopy

Abstract

AbstractWe report surface‐enhanced Raman spectroscopy (SERS) measurements on nanostructured gold surfaces prepared using a primary vacuum sputtering technique. Even if no molecules have been deposited on the metallic surface, a clear Raman signal is observed. A very intense and sharp peak around 2,100 cm−1 together with low‐wavenumber modes are visible. The comparison between the experimental spectra and those obtained using density functional theory calculations confirms that these new modes are associated with the cyanide compound Au(CN)2−. This proves the high sensitivity of SERS for the chemical analysis of metallic surfaces. It also shows that the pollution should be carefully taken into account in SERS analysis. We also demonstrate that high power laser illumination transforms these toxic compounds into carbon species; this method can be used to clean SERS substrates.