Fabrication of three-dimensionally ordered macroporous Ta2O5 films through aqueous organic gel process

Ta2O5 thin films have been prepared in the forms of three-dimensionally ordered macroporous (3-DOM) materials through aqueous organic gel process guided by polystyrene (PS) colloidal templates. The structure of the films was strongly affected by the infiltration process. This suggests that the infiltration process which aims at introducing desired materials into the interstitial spaces between the PS templates is of critical importance. Dip-drawing method was adopted for infiltration in this article. However, excess precursor worked as a capping agent for films prepared from the precursor of high concentration. Spin-coating method can efficiently remove the excess precursor by high speed rotating, which makes it a promising process for the infiltration of Ta-citric precursor with concentration higher than 0.5 mol/L. X-ray diffraction (XRD) pattern showed that the products can crystallize at 600 °C and had a pure orthorhombic phase. The chemical composition of the product was also studied by X-ray photoelectron spectroscopy (XPS).