Highly Polarized SERS Based on Random Working Domains Composed of Nanorod Arrays for Self-Referenced Detection

Abstract

When Ag film is sputtered onto polystyrene (PS) spheres, the curved Ag nanocaps form with scattered Ag nanoparticles along the brim of the Ag nanocap. Ion etching results in parallel PS nanorods due to the masking effects of the scattered Ag nanoparticles when the Ag cap array is transferred to another substrate with the top down. The highly polarized SERS substrate of random working domains composed of parallel nanorods is prepared when another 5 nm film is deposited. The nanorod diameters range from 10 nm to 20 nm, depending on the sizes of the masking Ag nanoparticles prepared by the magnetron control system and the ion etching process. Compared with other techniques, our nanorods have the advantages of highly ordered patterns in each domain, which show the excellent behavior of the polarized SERS for all PS spheres. This polarized SERS substrate is used to detect thiram with a concentration as low as 10−9 M when the background noise is successfully removed by a self-reference technique.