Search

Understanding resonant coupling in plasmonic nanoassemblies is a challenging scientific endeavor, especially for particles with complex nanoarchitectures. Our ability to both model and measure this...

Leveraging recent advances in electron energy monochromation and aberration correction, we record the spatially resolved infrared plasmon spectrum of individual tin-doped indium oxide nanocrystals using electron energy-loss spectroscopy (EELS). Both surface and bulk plasmon responses are measured as a function of tin doping concentration from 1-10 atomic percent. These results are compared to theoretical models, which elucidate the spectral detuning of the same surface plasmon resonance feature when measured from aloof and penetrating probe geometries. We additionally demonstrate a unique approach to retrieving the fundamental dielectric parameters of individual semiconductor nanocrystals via EELS. This method, devoid from ensemble averaging, illustrates the potential for electron-beam ellipsometry measurements on materials that cannot be prepared in bulk form or as thin films.

The Au–Al alloy system was investigated via a combinatorial thin film sputtering method for its potential as a plasmonic material. AuxAl1–x combinatorial libraries were cosputtered from Au and Al elemental targets and the composition, phase, and dielectric function of a ∼350 nm film was determined using energy dispersive spectroscopy (EDS), grazing incidence X-ray diffraction (GIXRD), and spectroscopic ellipsometry, respectively. The phase evolution and optical properties were analyzed after annealing various compositions under a vacuum. The phases present matched the expected phases based on the published Al–Au binary phase diagram at all compositions. Interestingly, the mixed phase Al-AuAl2 region showed the most optical tunability, where a maximum in the real part of the dielectric function progressively shifted to higher energy for increasing gold concentration. For almost pure AuAl2, the imaginary component is largely reduced in the visible range and is comparable to that of pure Al in the UV region....

In this Letter, we exploit recent breakthroughs in monochromated aberration-corrected scanning transmission electron microscopy (STEM) to resolve infrared plasmonic Fano antiresonances in individual nanofabricated disk-rod dimers. Using a combination of electron energy-loss spectroscopy (EELS) and theoretical modeling, we investigate and characterize a subspace of the weak coupling regime between quasi-discrete and quasi-continuum localized surface plasmon resonances where infrared plasmonic Fano antiresonances appear. This work illustrates the capability of STEM instrumentation to experimentally observe nanoscale plasmonic responses that were previously the domain only of higher resolution infrared spectroscopies.

The Au-Al alloy system was investigated via a combinatorial thin film sputtering method for its potential as a plasmonic material. Au