Two-Dimensional Ceramic Photonic Crystals Fabricated by a Solution Method

We fabricated two-dimensional hexagonal arrays of nanoscale ceramic pillars of titania or barium titanate. Precursor arrays were prepared by introducing sol solutions into electron-beam resist molds with air holes and subsequently dry etching unnecessary precursor layers on the molds. Ceramic arrays, consisting of dense titania or barium titanate ceramic pillars with a radius of 55–85 nm and a height of 500–550 nm, were fabricated by firing the precursor arrays at 773–1073 K. The reflection peaks for the ceramic arrays in the visible range almost correspond to the band structures calculated by a plane-wave method.