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Low-Loss and Tunable Localized Mid-Infrared Plasmons in Nanocrystals of Highly Degenerate InN
journal contribution
posted on 2018-08-23, 00:00 authored by Sadegh Askari, Davide Mariotti, Jan Eric Stehr, Jan Benedikt, Julien Keraudy, Ulf HelmerssonPlasmonic
response of free charges confined in nanostructures of
plasmonic materials is a powerful means for manipulating the light-material
interaction at the nanoscale and hence has influence on various relevant
technologies. In particular, plasmonic materials responsive in the
mid-infrared range are technologically important as the mid-infrared
is home to the vibrational resonance of molecules and also thermal
radiation of hot objects. However, the development of the field is
practically challenged with the lack of low-loss materials supporting
high quality plasmons in this range of the spectrum. Here, we demonstrate
that degenerately doped InN nanocrystals (NCs) support tunable and
low-loss plasmon resonance spanning the entire midwave infrared range.
Modulating free-carrier concentration is achieved by engineering nitrogen-vacancy
defects (InN1–x, 0.017 < x < 0.085) in highly degenerate NCs using a nonequilibrium
gas-phase growth process. Despite the significant reduction in the
carrier mobility relative to intrinsic InN, the mobility in degenerate
InN NCs (>60 cm2/(V s)) remains considerably higher
than
the carrier mobility reported for other materials NCs such as doped
metal oxides, chalcogenides, and noble metals. These findings demonstrate
feasibility of controlled tuning of infrared plasmon resonances in
a low-loss material of III–V compounds and open a gateway to
further studies of these materials nanostructures for infrared plasmonic
applications.