Enhanced Electromagnetic Coupling in the Walnut-Shaped Nanostructure Array

Abstract

It is a challenging yet valuable work to prepare a surface-enhanced Raman scattering (SERS) substrate with low cost and high performance by simple methods. In this study, the Ag nanoparticles were sputtered on PS spheres by the magnetron sputtering, which was used as the mask to create the nanostructures by etching the spheres. Because of the heating effect in the etching process, the Ag nanoparticles gathered on the surfaces of PS spheres when the etching time was 60 s. Strong electromagnetic coupling was observed between the gathered Ag nanoparticles as confirmed by FDTD simulation and SERS signals from the probe molecule 4-mercaptobenzoic acid. This structure showed the detection limit for thiram down to 10−8 M.