Structural and Optical Properties of Sol-Gel-Derived Au/BaTiO3 Nanocomposite Thin Films

Au/BaTiO3 nanocomposite thin films with different Au concentrations were prepared by a sol–gel process. The films were characterized using X‐ray diffraction, thermal analyses, X‐ray absorption spectroscopy, UV‐vis spectroscopy, and transmission electron microscopy. The effects of Au concentration and annealing temperature on the structural and optical properties of composite films were investigated. Gold doping lowered the crystallization temperature of as‐synthesized amorphous BaTiO3 and enhanced its crystallinity in post‐deposition annealing. The Au–BaTiO3 interface was also investigated and no alloying occurred between Au and BaTiO3. The evolution of Au surface plasmon resonance spectra with increasing annealing temperature was observed in the 10 mol% Au/BaTiO3 thin films. The variations of band‐gap energy for Au/BaTiO3 films were also discussed.