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Near-Infrared Optical Extinction of Indium Tin Oxide Structures Prepared by Nanosphere Lithography
journal contribution
posted on 2016-08-30, 00:00 authored by Misun Kang, Mark Losego, Edward Sachet, Jon-Paul Maria, Stefan FranzenIndium tin oxide
(ITO) has been the most widely studied conducting
metal oxide and serves as the best candidate for proof-of-concept
experiments in the field of surface plasmon resonance and studies
of electric field confinement and manipulation. ITO is chemically
stable and relatively easy to sputter. In this report, arrays of ITO
nanostructures were produced using nanosphere lithography, which was
originally developed for plasmonic applications involving noble metals.
However, the experiments presented here show that patterned ITO with
similar size and shape to noble metals has an observed extinction
that corresponds to the epsilon-near-zero mode. The carrier density
of ITO nanostructure can be controlled by the postdeposition annealing
process. Thus, one can prove that the optical signals on the surface
are those of the ITO nanostructure by reversible on/off switching
of the capacitive plasmon resonance by annealing the surfaces successively
in forming gas (N2/H2) and in air. Thus, using
conducting metal oxides confident of the electric field is possible
not only along the z-axis perpendicular to the thin
film but within the plane of the film as well.