Photonic Band Gap Properties of Three-Dimensional SiO₂ Photonic Crystals

Three-dimensional SiO₂ photonic crystals (PhCs) are fabricated on quartz substrates by the vertical deposition method. Scanning electron microscopy measurement reveals that the samples exhibit an ordered close-packed arrangement of SiO₂ spheres. It is found that the position of the 111 photonic band gap (PBG) shifts to a long wavelength (red shift) with increasing sphere size. Gap broadening effects are observed due to the presence of defects in the samples. Moreover, the optical properties of the PBG are very sensitive to the annealing temperature. Our results indicate that the optical properties of the PBG can be easily tuned in the visible region by appropriate experimental parameters, which will be useful for practical applications of PhC optical devices.