Fabrication of Two-dimensional Arrays of Graded Oxide Thin Films by the LPI Method

摘要

Two-dimensional graded metal oxide films with highly ordered periodic structure have been prepared from aqueous metal-fluoro complex solutions by liquid-phase infiltration (LPI) in an aqueous solution. Films were deposited from a solution, in which a (NH_4)_2 TiF_6 solution was added at a controlled flow rate into an FeOOH-NH_4F·HF solution. Field emission scanning electron microscopy (FE-SEM) reveals that the resultant graded oxide structures have highly nano-ordered architectures and represent negative or positive replicas of the template. Transmission electron microscopy (TEM) and X-ray microanalysis of the films revealed that the present technique enabled wide-range control of the composition and graded profile of the deposited films in the depth direction. Along with the change in composition, the microstructure of the films changes from microcrystalline β-FeOOH at the base to nanocrystalline anatase-TiO_2. The LPI process is conducive to the preparation of advanced nanoceramics with highly ordered structures.