Vertically Aligned Ag_xAu_{1- x} Alloyed Nanopillars Embedded in ZnO as Nanoengineered Low-Loss Hybrid Plasmonic Metamaterials

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_xAu_1-x alloy nanopillars embedded in a ZnO matrix has been successfully grown. The chemical composition of the nanoalloy was determined to be Ag₆₁Au₃₉. The microstructure and optical properties arising from ZnO-Ag₆₁Au₃₉ 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-Ag₆₁Au₃₉ 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.