Fabrication and optical reflection behavior of a two-dimensional barium titanate ceramic photonic crystal

We demonstrate a method for fabricating a two-dimensional hexagonal array of nanoscale barium titanate ceramic pillars. A precursor array was prepared by introducing a sol solution into an electron-beam resist mold with air holes and subsequently dry etching the unnecessary gel layer formed on the mold. A ceramic array, consisting of barium titanate ceramic pillars with a radius of 85 nm, a lattice constant of 450 nm, and a height of 500 nm, was fabricated by sintering the precursor array at 1073 K. The reflection spectra for the ceramic array in the visible range revealed the underlying photonic band gaps, which were in good agreement with results calculated using a plane-wave method.