Three-Dimensional Characterization of Morphology and Crystallography of a Gold Nanoisland Film

The morphological and crystallographic characteristics of noble metal nanoisland films play an important role in determining their properties, performance, and reliability. In this work we have applied a rapid three-dimensional orientation mapping technique in the transmission electron microscope (3D-OMiTEM) in the characterization of a gold nanoisland film. A volume of 200×1024×1024 nm3 has been analyzed, generating a 3D orientation map composed of more than 500 nanoislands and 7000 grains constituting the islands. The 3D shapes and sizes of individual islands and grains have been analyzed, revealing their true 3D morphological features and the correlation between the number of grains within individual islands and the size of the islands. The crystallographic orientations of the grains and the misorientations across the grain boundaries have been quantified, revealing a weak texture but a preferential presence of Σ3 and Σ9 grain boundaries in the gold nanoisland film.

Optical Properties of Electrically Active Gold Nanoisland Films Enabled with Interfaced Liquid Crystals

A system comprising a gold nanoisland film (Au NIF) covered with a liquid crystal (LC) material is introduced. By applying a voltage across the LC bulk, we demonstrate that changes in the refractive-index and orientation significantly modified the hybrid plasmonic–photonic resonances of the Au NIF. The hybrid structure enabled active control of the spectrum of the resonance wavelength of the metallic nanoisland by means of an externally applied electric field. Our modeling supports the observed results in LC/Au NIF. In a combination of the nanostructured surface with birefringent LCs, nonpolarized wavelength tunability of ~15 nm and absorbance tunability of ~0.024 were achieved in the visible wavelength, opening the door to optical devices and nanoscale sensors.