Abstract: The present invention related to surface-enhanced Raman spectroscopy (SERS) substrates that are adsorbable and flexible comprises a polymeric base with detailed specific embossed structures on the surface and noble metal nanoparticles coated on the polymeric base, wherein the capillary effect is exhibited by the nanometer-sized rough features embedded in the micrometer-sized stripe patterns on the surface of the embossed polymeric base, the distances between the coated noble metal nanoparticles are between 50-200 nm to allow for sufficient number of hot spots for high Raman signal enhancement, the ridge width of the embossed stripe pattern is between 15-80 pm, and the distance between the ridges of the embossed stripe pattern is 0.04-0.14 mm.

Abstract: The present invention provides a process of making 3D-structured SERS substrates by using a laser marking machine as part of the fabrication procedures. The 3D-structured SERS substrates in the present invention comprises of a roughened metal sheet on which noble metal nanoparticles are coated. Rough structures on the metal sheet are created by a laser marking machine. Noble metal nanoparticles are deposited onto the substrates in a magnetron sputtering system. The specific parameters involved in the settings of a laser marking machine include a laser power in a range of 1-20 W, fill spacing of 0.02-0.15 mm, speed of 1-10,000 mm/s, frequency of 20-200 kHz and repetition rate of 1-50 times. The 3D-structured SERS substrates in the present invention are able to give high enhancement of Raman signals and can detect methylene blue solution with concentration as low as 1×1O?6 M.