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.

Fabrication of silver nanoparticles decorated anodic aluminum oxide as the SERS substrate for the detection of pesticide thiram

An efficient surface-enhanced Raman scattering(SERS) substrate is developed based on silver nanoparticles decorated anodic aluminum oxide(Ag/AAO).The AAO templates were fabricated using a two-step anodization approach,and silver nanoparticles(Ag NPs) were obtained by thermal decomposition of Ag nitrate in AAO.The structure of Ag/AAO hybrid substrate is characterized by scanning electron microscopy(SEM).The results show that the as-prepared SERS substrates consist of high-density Ag NPs with sizes of tens of nanometers.The Ag NPs are adsorbed on the surface of AAO template in the form of network structure which is called "hot spot".The SERS enhancement ability of the nanostructure is verified using thiram as probing molecules.The limit of detection is as low as 1×10-9 mol/L.The results indicate that the as-prepared substrate possesses excellent SERS sensitivity,high stability and uniformity enhancement.