SERS in Ordered Array of Geometrically Controlled Nanodots Obtained Using Anodic Porous Alumina

The fabrication of geometrically controlled nanodot arrays based on anodic porous alumina and their application as substrates used for surface-enhanced Raman scattering (SERS) measurements were studied. Ordered arrays of circular, square, and triangular Au nanodots were obtained using anodic porous alumina as an evaporation mask. The shape and arrangement of the nanodots were precisely controlled by adjusting the geometrical structure of the nanoholes in the anodic porous alumina. We also fabricated triangular nanodots that had sharp corners with a curvature radius of 15 nm. SERS spectra of pyridine molecules adsorbed on the Au nanodots were measured using the obtained nanodot arrays as substrates for measurements. The SERS intensity obtained from the triangular nanodot array was strongly enhanced compared with that obtained from the array of circular nanodots. The intensity of signals was dependent on the shape and arrangement of the nanodots. It is expected that nanodot arrays obtained by this fabrication method using anodic porous alumina can be used for the formation of functional optical devices requiring an ordered array of geometrically controlled nanostructures.