nn6b02911_si_liveslides.zip (6.07 MB)
Plasmonic Heating in Au Nanowires at Low Temperatures: The Role of Thermal Boundary Resistance
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posted on 2016-07-27, 14:35 authored by Pavlo Zolotavin, Alessandro Alabastri, Peter Nordlander, Douglas NatelsonInelastic electron tunneling and
surface-enhanced optical spectroscopies
at the molecular scale require cryogenic local temperatures even under
illuminationconditions that are challenging to achieve with
plasmonically resonant metallic nanostructures. We report a detailed
study of the laser heating of plasmonically active nanowires at substrate
temperatures from 5 to 60 K. The increase of the local temperature
of the nanowire is quantified by a bolometric approach and could be
as large as 100 K for a substrate temperature of 5 K and typical values
of laser intensity. We also demonstrate that a ∼3-fold reduction
of the local temperature increase is possible by switching to a sapphire
or quartz substrate. Finite element modeling of the heat dissipation
reveals that the local temperature increase of the nanowire at temperatures
below ∼50 K is determined largely by the thermal boundary resistance
of the metal–substrate interface. The model reproduces the
striking experimental trend that in this regime the temperature of
the nanowire varies nonlinearly with the incident optical power. The
thermal boundary resistance is demonstrated to be a major constraint
on reaching low temperatures necessary to perform simultaneous inelastic
electron tunneling and surface-enhanced Raman spectroscopies.