3D patterning of Ag nanoparticles by ULE ion implantation and stencil soft lithography for plasmonic device applications

Combining ultra-low-energy ion beam synthesis (ULE-IBS) and stencil mask fabrication is shown to be well adapted for obtaining—in a single step—3D patterns of embedded metallic nanoparticles assemblies. We demonstrate how it offers new opportunities particularly well adapted to high throughput and large scale applications in plasmonics. We originally developed this method to get silver (Ag) nanoparticle (NPs) planar arrays embedded in silica (SiO2) on a silicon substrate. Shallow nanometer-sized Ag NPs structures exhibiting surface plasmon resonance are then synthesized at few nm below the surface. The maps of the Ag NPs Raman response perfectly correlate the structural images obtained by SEM and AFM. In addition, the AFM surface profile suggests an in-plane diffusion of the silver: fabrication issues such as diffusion and surface sputtering are discussed.