Highly-ordered, 3D petal-like array for surface-enhanced Raman scattering.

Despite the great potential of the application of surface-enhanced Raman scattering (SERS), the difficulty in fabricating suitable SERS substrates is still a problem. Based on the self-assembly of silica nanoparticles, a simple method is here proposed to fabricate a highly-ordered, 3D, petal-like arrayed structure (3D PLAS) that serves as a promising SERS substrate for both its high reproducibility and enormous SERS enhancement. Such a novel structure is easily achieved by anisotropically etching a self-assembly bilayer of silica nanoparticles, followed by metal deposition. The SERS performance of the 3D PLAS and its relationship with the main parameters, including the etching time, the diameter of silica nanoparticles, and the deposited metal film, are characterized using 632.8 nm incident light. With Rhodamine 6G as a probe molecule, the spatially averaged SERS enhancement factor is on the order of 5 × 10(7) and the local enhancement factor is much higher, both of which can be improved further by optimizing the parameters.