Engineered Self‐Assembly of Plasmonic Gold Nanoparticles Into Two‐Dimensional and Three‐Dimensional Arrays Within the Pores of Porous Silicon Membranes

We report a facile centrifugation-based method for assembling polystyrene (PSSH)-functionalized gold nanoparticles (Au NPs)onto porous silicon (pSi) substrates in two distinct configurations: two- and three-dimensional (2D and 3D) assemblies. The 2Dassemblies are densely packed monolayer coatings of the exposed Si-surfaces including the inner pore walls, whereas the 3Dstructures result from Au NPs clustering inside the pores. Remarkably, this shift from 2D to 3D architectures was achievedby minor modification of the PSSH coating thickness. Scanning electron microscopy (SEM) characterization confirmed the homo-geneity and high packing density of these assemblies extending over several thousand square micrometers. This approach offers astraightforward and versatile route for the fabrication of well-ordered pSi–Au NP hybrid nanostructures with potential applica-tions in catalysis, surface-enhanced spectroscopy and optical metamaterials.