GaP nanocones covered with silver nanoparticles for surface-enhanced Raman spectroscopy

This work describes the preparation of surface-enhanced Raman spectroscopy (SERS) substrates based on GaP nanocones decorated with Ag nanoparticles. The GaP nanocones were grown by metal organic vapour phase epitaxy and then covered with silver nanoparticles produced by a simple electroless method from a silver nitrate solution. The Ag nanoparticle/GaP nanocone structure acted as an effective SERS substrate as it exhibited a significantly higher Raman signal sensitivity compared with that of a planar GaP substrate covered with Ag nanoparticles. The three-dimensional Ag nanoparticle/GaP nanocone substrate was shown to be appropriate for SERS applications, which was demonstrated by the detection of Rhodamine 6G delivered onto the substrate from an aqueous Rhodamine 6G solution at a concentration of 10(-2) M.