Micropatterned Silica Films with Ordered Nanopores Fabricated through Photocalcination

Nanoporous silica was formed into micropatterned thin films based on the area-selective growth of silica−organic nanocomposite films and the subsequent elimination of the organic components. To eliminate organic molecules from the nanocomposite, a photochemical approach, that is, “photocalcination”, using a vacuum ultraviolet light of 172 nm wavelength was employed. As confirmed by infrared spectroscopy, atomic force microscopy and X-ray diffractometry, the organic phase was completely removed from the nanocomposite by photocalcination without distorting either its well-ordered nanostructure or its finely patterned microstructures. Photocalcination is advantageous compared with the conventional thermal approach, that is, calcination, since it may be conducted at room temperature. In comparison, volume shrinkage of the silica-based nanocomposite microstructures due to photo- or thermocalcination was about 5% and 30%, respectively.