Large-scale synthesis of gold dendritic nanostructures for surface enhanced Raman scattering

Abstract

Au dendritic nanostructures with sharp tips have been successfully fabricated on a large scale by reducing potassium tetrachloroaurate (KAuCl₄) with hydrofluoric acid on a Si wafer locally processed using a focused ion beam (FIB) technique. Surface enhanced Raman scattering (SERS) with Rhodamine B (RhB) molecules on a nanostructured substrate is greatly enhanced, originating from “hot-spots” located at the nanogaps between adjacent branches on dendritic nanostructures. Furthermore, Au dendritic nanostructures as recyclable SERS substrates exhibit an ultrasensitive response to the pico-scale concentration of probe molecules. This work shows that greatly enhanced SERS substrates with a high degree of reliability and reproducibility can be fabricated at a relatively low cost, which could help SERS to realize its full potential as a very sensitive tool for trace analysis.