title: Preparation of a SERS substrate and its sample-loading method for point-of-use application.
abstract: A simple approach was demonstrated to prepare a silver (Ag) nanoparticle (NP) assembly as a SERS substrate. Just by dipping a flat silicon (Si) wafer into an aqueous deposition solution of hydrogen fluoride (HF) + silver nitrate (AgNO3), a monolayer of Ag NPs was uniformly deposited onto the Si wafer surface. In order to load the to-be-detected sample onto the as-prepared SERS substrate, three methods have been individually tested, (i) by incubating the SERS substrate in the sample solution, (ii) by dropping and drying a small volume of the sample solution (1-2 microl) onto the SERS substrate surface, or (iii) by directly introducing the sample into the deposition solution. The last approach was also employed to metalize a Si nanowire (NW). Due to the NW's highly curved surface, the Ag NPs self-assembled and aggregated along the NW with a close interdistance. The aggregated Ag NPs on the NW surface can also be used as a SERS substrate. The demonstrated approach holds the promise to prepare a fresh SERS substrate at the point-of-use with the sample already loaded to promptly collect the SERS signal for the field application.
authors.affiliation: Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore.
authors.forename: C
authors.initials: C
authors.lastname: Fang
authors.forename: A
authors.initials: A
authors.lastname: Agarwal
authors.forename: H
authors.initials: H
authors.lastname: Ji
authors.forename: W Y
authors.initials: WY
authors.lastname: Karen
authors.forename: L
authors.initials: L
authors.lastname: Yobas
mesh_terms: D006858:Hydrofluoric Acid / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology / Q000379:methods*; D012834:Silver / Q000737:chemistry*; D012835:Silver Nitrate / Q000737:chemistry; D013059:Spectrum Analysis, Raman
chemical_list: D012834:Silver; D012835:Silver Nitrate; D006858:Hydrofluoric Acid