Au–Cu Alloyed Plasmonic Layer on Nanostructured GaN for SERS Application

The main aim of this work was developing a novel technology for producing platforms for surface enhanced Raman scattering (SERS) measurements on photoetched (nanostructured) GaN with Au–Cu thin film as surface plasmonic layer. Dealloying of deposited Au–Cu films gives very stable and SERS-active platforms. Influence of percentage of copper in the alloyed Au–Cu layer on the SERS enhancement factor (EF SERS ) was examined. SERS measurements were performed using pyridine and 4-mercaptobenzoic acid. Corresponding GaN platforms covered with Au and Au–Ag layers were used as a reference. It was also shown that the formation of even relatively large (above 1 μm) and very regular etch pits on the GaN surface may significantly increase the SERS enhancement factor.