Enhancement of Surface Raman Spectroscopy Performance by Silver Nanoparticles on Resin Nanorods Arrays from Anodic Aluminum Oxide Template

Abstract

The surface enhanced Raman spectroscopy (SERS) substrates were fabricated by many methods including the AAO molding and high-cost nanolithography-etching-deposition process. In this article, we have demonstrated the SERS substrate fabricated with silver nanoparticles (Ag-NP) electroless deposition on highly ordered dense hexagonal arrays of UV curable resin nanorods (R-NR) arrays which was reproducible from a precisely controlled anodic aluminum oxide (AAO) template. This method could improve the non-flatness induced defect problem in the conventional nanoimprinting technique and form high-quality duplications of nanometer templates. The periodic hierarchical double-structured nanorods arrays with small nanorods (diameter about 30∼40 nm) in large nanorods (diameter about 100∼110 nm) were obtained by the UV curable resins molding from the AAO template. Two kinds of electroless deposition i.e. self-assembly and ultrasonic vibration methods were performed for Ag-NP formation on R-NR. The enhancement factors of SERS using 10−5 M methylene blue (MB) as probing molecules were 104∼106 for the self-assembled method and 105∼107 for the ultrasonic vibration one, respectively. This was because the ultrasonic vibration deposition could result in Ag nanorods arrays with higher regularity and contact area than the self-assembly one.