Silver coated nickel nanotip arrays for low concentration surface enhanced Raman scattering

Abstract

A two-step glancing angle deposition method is developed to fabricate hierarchical metal nanostructures for surface enhanced Raman scattering (SERS). Nanotip arrays, which consist of a thin layer of silver on nickel nanoneedles, are deposited on silicon substrates by this method. Rhodamine 6G (R6G) is used to demonstrate the sensitivity of SERS at the near attomolar level. The scaling of Raman intensity with the concentration of R6G is related to the Langmuir-Freundlich isotherm.