title: Focusing plasmons in nanoslits for surface-enhanced Raman scattering.
abstract: The focusing of plasmons to obtain a strong and localized electromagnetic-field enhancement for surface-enhanced Raman scattering (SERS) is increasing the interest in using plasmonic devices as molecular sensors. In this Full Paper, we report the successful fabrication and demonstration of a solid-state plasmonic nanoslit-cavity device equipped with nanoantennas on a freestanding thin silicon membrane as a substrate for SERS. Numerical calculations predict a strong and spatially localized enhancement of the optical field in the nanoslit (6 nm in width) upon irradiation. The predicted enhancement factor of SERS was 5.3 x 10(5), localized in an area of just 6 x 1.5 nm(2). Raman spectroscopy and imaging confirm an enhancement factor of approximately 10(6) for SERS from molecules chemisorbed at the nanoslit, and demonstrate the electromagnetic-field-enhancing function of the plasmonic nanoantennas. The freestanding membrane is open on both sides of the nanoslit, offering the potential for through-slit molecular translocation studies, and opening bright new perspectives for SERS applications in real-time (bio)chemical analysis.
authors.affiliation: IMEC vzw Kapeldreef 75, 3001 Leuven, Belgium. chang.chen@imec.be
authors.forename: Chang
authors.initials: C
authors.lastname: Chen
authors.forename: James Andell
authors.initials: JA
authors.lastname: Hutchison
authors.forename: Pol
authors.initials: P
authors.lastname: Van Dorpe
authors.forename: Ronald
authors.initials: R
authors.lastname: Kox
authors.forename: Iwijn
authors.initials: I
authors.lastname: De Vlaminck
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uji-I
authors.forename: Johan
authors.initials: J
authors.lastname: Hofkens
authors.forename: Liesbet
authors.initials: L
authors.lastname: Lagae
authors.forename: Guido
authors.initials: G
authors.lastname: Maes
authors.forename: Gustaaf
authors.initials: G
authors.lastname: Borghs
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008567:Membranes, Artificial; D036103:Nanotechnology / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D008567:Membranes, Artificial