1 research outputs found
Mapping Photoemission and Hot-Electron Emission from Plasmonic Nanoantennas
Understanding plasmon-mediated
electron emission and energy transfer
on the nanometer length scale is critical to controlling light–matter
interactions at nanoscale dimensions. In a high-resolution lithographic
material, electron emission and energy transfer lead to chemical transformations.
In this work, we employ such chemical transformations in two different
high-resolution electron-beam lithography resists, polyÂ(methyl methacrylate)
(PMMA) and hydrogen silsesquioxane (HSQ), to map local electron emission
and energy transfer with nanometer resolution from plasmonic nanoantennas
excited by femtosecond laser pulses. We observe exposure of the electron-beam
resists (both PMMA and HSQ) in regions on the surface of nanoantennas
where the local field is significantly enhanced. Exposure in these
regions is consistent with previously reported optical-field-controlled
electron emission from plasmonic hotspots as well as earlier work
on low-electron-energy scanning probe lithography. For HSQ, in addition
to exposure in hotspots, we observe resist exposure at the centers
of rod-shaped nanoantennas in addition to exposure in plasmonic hotspots.
Optical field enhancement is minimized at the center of nanorods suggesting
that exposure in these regions involves a different mechanism to that
in plasmonic hotspots. Our simulations suggest that exposure at the
center of nanorods results from the emission of hot electrons produced
via plasmon decay in the nanorods. Overall, the results presented
in this work provide a means to map both optical-field-controlled
electron emission and hot-electron transfer from nanoparticles via
chemical transformations produced locally in lithographic materials