Silicon nano-structure fabrication and application for surface-enhanced Raman spectroscopy
We demonstrated fabrication of black silicon with slanted nano-pillar array on both planar and 3D micro- and mesoscale structures produced by a high-throughput lithography-free oblique-angle plasma etching process. Nano-pillars with gradual change in height were created on the same piece of silicon. The relation between the slant angle of nano-pillars and incident angle of directional plasma is experimentally investigated. In order to demonstrate the monolithic integration of nano-structures on micro- and mesoscale nonplanar surfaces, a nano-pillar forest is fabricated on nonplanar silicon surfaces in various morphologies such as silicon atomic force microscopy (AFM) tips and pyramidal pits. By integrating nano-pillars on inverse silicon micro-pyramid array devices, we further improved the surface-enhanced Raman scattering (SERS) enhancement property of this optimized commercial SERS substrate by severalfold even when using 66% less noble metal coating. We investigated the length gradient dependence and asymmetric properties of SERS effects for slanted nano-pillar with polarized excitation. This versatile and angle-controllable nano-pillar fabrication and monolithic 3D nano–micro–meso integration method provides new dimensions for production and optimization of SERS and other nano-photonic sensors.
nano, fabrication, Raman, spectroscopy, silicon
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign