Vertically Aligned Ag<sub><i>x</i></sub>Au<sub>1-<i>x</i></sub> Alloyed Nanopillars Embedded in ZnO as Nanoengineered Low-Loss Hybrid Plasmonic Metamaterials.

Paldi, Robynne L; Wang, Xuejing; Sun, Xing; He, Zihao; Qi, Zhimin; Zhang, Xinghang; Wang, Haiyan · Nano Lett · 2020

basic_science · Level V

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Abstract

Hybrid plasmonic metamaterials offer a pathway to exotic properties and technologically important applications including subdiffraction imaging and plasmonic energy harvesting. Challenges remain for practical applications including high absorption losses of noble metals and tedious growth/fabrication processes. In this work, a self-assembled hybrid plasmonic metamaterial consisting of anisotropic Ag<sub><i>x</i></sub>Au<sub>1-<i>x</i></sub> alloy nanopillars embedded in a ZnO matrix has been successfully grown. The chemical composition of the nanoalloy was determined to be Ag<sub>61</sub>Au<sub>39</sub>. The microstructure and optical properties arising from ZnO-Ag<sub>61</sub>Au<sub>39</sub> alloyed hybrid systems were investigated and compared with that of the ZnO-Ag particle-in-matrix nanocomposite and the ZnO-Au vertically aligned nanocomposite. The ZnO-Ag<sub>61</sub>Au<sub>39</sub> hybrid system demonstrates anisotropic morphology, excellent epitaxial quality, and enhanced optical properties, including surface plasmon resonance, hyperbolic dispersion, low absorption losses, and numerous epsilon-near-zero permittivity points, making it a promising candidate for practical applications of hybrid plasmonic metamaterials.