A Review: Nanofabrication of Surface-Enhanced Raman Spectroscopy (SERS) Substrates

Standard Raman spectroscopy coupled with metal nanostructures, known as surface-enhanced Raman spectroscopy (SERS), has exhibited great potential in detecting molecules at trace levels. Translating this profound phenomenon into practical applications requires reliable and scalable approaches to manufacture SERS-active metal nanostructures, so-called SERS substrates, with well controlled quality. Following a review on the fundamental aspects of SERS, this paper summarizes a broad spectrum of nanofabrication methods that have been employed for SERS substrates and groups these nanofabrication techniques into three categories: lithography based methods, non-lithography template methods, and direct formation. It should be noted that this review focuses on on-chip SERS substrates and the colloidal nanoparticles-based SERS substrates are not in the discussion. In the end of the review, the paper also briefly discusses several commercialized SERS substrates on the market.