Gold-coated nanorod arrays as highly sensitive substrates for surface-enhanced raman spectroscopy

Substrates for surface-enhanced Raman spectroscopy (SERS) have suffered from low enhancement, short shelf time, and poor uniformity or reproducibility. We report an effective method to produce SERS substrates that can potentially overcome these shortcomings. The SERS substrate consists of a layer of 100 nm Ag film deposited on a Si or glass substrate, a Si nanorod array fabricated by glancing angle deposition, and an Au coating fabricated by sputtering. The effects of the height and separation of the Si nanorods and the thickness of the Au layer on the SERS enhancement factor are investigated. Optimal substrates are capable of detecting attomolar quantities of trans-1,2-bis(4-pyridyl)ethylene.