Template assisted deposition of Ag nanoparticle arrays for surface-enhanced Raman scattering applications

In this work, we describe a simple cost-effective method to prepare highly ordered arrays of Ag nanodisks on Si for surface-enhanced Raman scattering applications. A porous alumina template mask is transferred onto a metal-coated Si wafer and used to electrodeposit hexagonal patterns of Ag nanoparticles with tunable diameters and spacing. The SERS activities of well-ordered nanodot arrays with two different ratios of particle diameter to interparticle spacing are measured using phenylethyl mercaptan as the probe molecule. By increasing the particle diameter to interparticle spacing ratio from 2.1 to 7.3, the SERS enhancement is augmented by nearly one order of magnitude, reaching values in excess of 107. The excellent uniformity of these nanoarrays and the reproducibility of the resulting SERS intensities offer a powerful tool for the detection of chemical and biological species with high sensitivity.