Log-Pile TiO2 Photonic Crystal for Light Control at Near-UV and Visible Wavelengths

Three-dimensional photonic crystals with an omnidirectional bandgap at visible frequencies can have significant impact on solid-state lighting and solar-energy conversion. Using a procedure based on multistep electron-beam lithographic processing, a 9-layer log-pile photonic crystal is fabricated composed of 70-nm-wide titanium dioxide rods with 250-nm lattice spacing that exhibit a stacking direction bandgap between 400 nm and 500 nm (see image).