title: Functional plasmonic antenna scanning probes fabricated by induced-deposition mask lithography.
abstract: We have fabricated plasmonic bowtie antennae on the apex of silicon atomic-force microscope cantilever tips that enhance the local silicon Raman scattering intensity by approximately 4 x 10(4) when excited near the antenna resonance. The antennae were fabricated using a novel method, induced-deposition mask lithography (IDML), capable of creating high-purity metallic nanostructures on non-planar, non-conducting substrates with high repeatability. IDML involves electron-beam-induced deposition of a W or SiO(x) hard mask on the material to be pattered, here a 20 nm Au film, followed by Ar ion etching to remove the mask and the unmasked gold, leaving a chemically pure Au bowtie antenna. Antenna function and reproducibility was confirmed by comparing Raman spectra for excitation polarized parallel and perpendicular to the antenna axis, as well as by dark-field spectroscopic characterization of resonant modes. The field enhancement of these plasmonic AFM antennae tips was comparable with antennae produced by electron-beam lithography on flat substrates.
authors.affiliation: Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. afweber-bargioni@lbl.gov
authors.forename: A
authors.initials: A
authors.lastname: Weber-Bargioni
authors.forename: A
authors.initials: A
authors.lastname: Schwartzberg
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.forename: B
authors.initials: B
authors.lastname: Harteneck
authors.forename: D F
authors.initials: DF
authors.lastname: Ogletree
authors.forename: P J
authors.initials: PJ
authors.lastname: Schuck
authors.forename: S
authors.initials: S
authors.lastname: Cabrini