Thermally Stable Au–BaTiO₃ Nanoscale Hybrid Metamaterial for High-Temperature Plasmonic Applications

The thermal stability of the Au–BaTiO3 nanocomposite thin film as a hybrid metamaterial deposited by a one-step pulsed laser deposition (PLD) method has been investigated via both ex situ annealing followed by TEM analysis and an in situ heating study in TEM. For the ex situ annealing study, the XRD analysis shows good crystallinity for both as-deposited and annealed films after being annealed at 600 °C for different time periods (i.e. 1, 3, 6, and 30 hours). The optical measurements including transmittance/reflectance, ellipsometry, and Raman spectroscopy demonstrate excellent optical properties of the hybrid metamaterial films by exhibiting the static localized surface plasmon resonance (LSPR) peak and hyperbolic dispersion in the visible to near-infrared regime. Both TEM results of the ex situ annealed samples and in situ heatingTEM results reveal no obvious microstructure change after the extensive high-temperature annealing and suggest the high thermal stability of the Au–oxide hybrid materials for their future high-temperature plasmonic applications.