Fabrication of arrayed triangular micro-cavities for SERS substrates using the force modulated indention process

Abstract

Based on the tip-based continuous indentation process, a novel method for the fabrication of periodic arrayed triangular micro-cavities on copper (Cu) surfaces is presented. The indentation force is modulated and the indentation speed and moving velocity of the precision stage used to drive the workpiece are optimized to improve the machining efficiency. The deformation property of the pile-ups at the side of the pyramidal cavity is studied. Due to the overlap of the pile-ups of adjacent micro pyramidal cavities, two and three dimensional arrayed nanostructures are successfully achieved. Then, the structured Cu (110) surface is used as a surface-enhanced Raman scattering (SERS) substrate with the rhodamine 6G (R6G) probe molecule as the detecting target in the present study. Experimental results show that the Raman intensity is enhanced with a decrease in the moving velocity of the precision stage. SERS enhancement factors within the range of 10⁵ to 3 × 10⁶ are achieved on the structured Cu (110) surface, which demonstrates that this method is reliable, replicable, homogeneous and inexpensive for the fabrication of SERS substrates.