Reusable surface-enhanced Raman substrates using microwave annealing

Abstract

In this work, we report the fabrication of large-scale homogeneous surface-enhanced Raman scattering (SERS) substrates using a microwave annealing (MWA) process on Ag thin films on silicon, using a typical low-cost domestic microwave oven, avoiding the use of chemicals and stabilizing agents, or time-consuming and expensive approaches. We provide evidence that in 5–15 s, uniform and reproducible SERS substrates of several centimeter squares can be grown, providing a Raman signal enhancement of five orders of magnitude, for an incident Raman laser with an intensity as low as ~ 0.035 mW, against the characterization of Rhodamine 6G, which is a standard test molecule for SERS. Moreover, we tested the reusability of the fabricated MWA SERS substrates under conditions as tough as ultrasonic sonication in isopropyl alcohol and acetone for 15 min, respectively, and we demonstrate that our SERS substrates can be efficiently reused for more than six times after sonication, which is quite critical since it minimizes the cost of the procedure to minimum.