Functional plasmonic antenna scanning probes fabricated by induced-deposition mask lithography.
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.
Weber-Bargioni
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A
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. afweber-bargioni@lbl.gov
Schwartzberg
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A
Schmidt
M
M
Harteneck
B
B
Ogletree
D F
DF
Schuck
P J
PJ
Cabrini
S
S