Silver hierarchical structures grown on microstructured silicon in chip for microfluidic integrated catalyst and SERS detector

In this Letter, silver(Ag) hierarchical nanostructures grown on black silicon(BS) are used as the catalyst and a surface-enhanced Raman scattering(SERS) detector integrated in a microfluid. The BS is fabricated via femtosecond laser ablation in an atmosphere of sulfur hexafluoride, and then hydrogenated with hydrofluoric acid. As formed, the BS substrate directly acts as a reducing template to grow silver hierarchical nano-structures.Particularly, Ag-BS composite micro/nano-structures can be in-situ constructed in silicon-based microchannels.These structures simultaneously serve as integrated catalytic reactors and a SERS substrate for sensing. The sensitivity is tested to be as low as 10-8mol∕L using Rhodamine 6G.