Liquid-Phase Infiltration (LPI) Process for the Fabrication of Highly Nano-Ordered Materials

A novel technique for the direct synthesis of twodimensional metal oxide films with highly ordered periodic structure has been studied. The technique involves liquid-phase infiltration (LPI) in an aqueous solution. 2D TiO2 structures with diameters ranging from 120 to 1065 nm are fabricated by filling the holes in a Si wafer using a solution of (NH4)2TiF6 and H3BO3 at ambient temperature, and subsequently peeling off the template. Field emission scanning electron microscopy (FESEM) reveals that the resultant TiO2 structures have highly nano-ordered architectures and represent negative and positive replicas of the template. The TiO2 structures are transferred from the template with precision; no voids or seams are introduced during the transfer. The film thickness or filling rate of TiO2 can be controlled by adjusting the reaction time. The LPI process is conducive to the preparation of advanced metal oxide films with highly ordered structures, and enables modification of optical properties of photonic crystals on a nanometer scale