title: Surface-enhanced-Raman-scattering-inducing nanoprobe for spectrochemical analysis.
abstract: This paper describes a new nanoprobe that induces the surface-enhanced Raman scattering (SERS) effect when brought into contact with chemicals on any type of surface. The SERS-inducing probe was fabricated from an optical fiber that was tapered to a tip 100 nm in diameter. A thin layer of silver islands was applied to the tip of the tapered fiber via thermal evaporation to induce the SERS effect. The small scale of the tip may be amenable to localized, nondestructive SERS-based analyses of surfaces with high spatial selectivity. Because the contact probe itself induces the SERS effect, no modification of the sample is required. Direct analysis at submicrometer spatial selectivity is therefore possible for analyte compounds on any type of surface. Various optimization studies and preliminary evaluations were performed. A 10-nm silver thickness was determined to yield the optimum SERS effect. A 25% relative standard deviation in SERS signal was observed for five different probe tips. As a demonstration of the SERS-inducing capability of the probe, Raman spectra were recorded for glass surfaces coated with brilliant cresyl blue and p-aminobenzoic acid before and during contact with the SERS-inducing nanoprobe.
authors.affiliation: Advanced Monitoring Development Group, Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6101, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Stokes
authors.forename: Zhenhuan
authors.initials: Z
authors.lastname: Chi
authors.forename: Tuan
authors.initials: T
authors.lastname: Vo-Dinh
mesh_terms: D010129:4-Aminobenzoic Acid / Q000032:analysis; D002138:Calibration; D004396:Coloring Agents / Q000032:analysis; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation; D005898:Glass; D007834:Lasers; D036103:Nanotechnology / Q000295:instrumentation*; D055100:Optical Fibers; D015203:Reproducibility of Results; D012834:Silver; D013059:Spectrum Analysis, Raman / Q000295:instrumentation*; D013499:Surface Properties
chemical_list: D004396:Coloring Agents; D012834:Silver; D010129:4-Aminobenzoic Acid