Preparation, structural and optical properties of Sol-gel derived Au/BaTiO3 thin films

Abstract

Au/BaTiO3 thin films with different Au concentrations were prepared by a sol-gel process. The structures and optical properties were investigated. The effects of annealing temperature and Au concentration on the structure of films were studied by XRD, TA, XAFS and TEM. It was found that Au exerted pronounced influence on the structural development of BaTiO3 matrix by lowering its crystallization temperature and enhancing its crystallinity. It was also observed that Au affected the formation and decomposition of an intermediate phase in the matrix. The Au-BaTiO3 interface was characterized by XAFS and HRTEM that showed clear phase separation. The evolution of Au SPR spectra with increasing annealing temperature was investigated in terms of Au particle size, dielectric constant of matrix and Au-BaTiO3 interface. The variations of band gap energy of BaTiO3 in Au/BaTiO3 films as a function of annealing temperature were related to the structural features of the films.