The preparation and formation mechanism of barium strontium titanate/silicon nanoporous pillar array composite film by sol-gel method

Abstract

Silicon nanoporous pillar array (Si-NPA) with micron/nanometer hierarchical structure was fabricated by hydrothermally etching method, and then the Ba 0.5 Sr 0.5 TiO 3 (BST) sol was spin-coated on Si-NPA substrate to form composite film. The structure, morphology and chemical formation mechanism of composite film were studied. The intrinsic structural characteristics of Si-NPA were inherited in composite film. BST xerogel underwent isomer conversion and formed chelate network structure combined by enol and Ti-alkoxid at high temperature, in which the chelating agent acetylacetone played a modulating role and facilitated the stabilization of the BST sol. The formation of BST perovskite structure via a solid-state reaction of intermediate phases (Ba, Sr)Ti 2 O 5 CO 3 . Annealed under 500 0 C, the composite film was amorphous, but it began to crystallize at 600 0 C. A well crystalline BST/Si-NPA composite film was achieved at the annealing temperature of 700 0 C.