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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.

The as-deposited Au/Ti/p-diamond contacts prepared by rf sputtering are ohmic. The ohmic characteristics of the contacts are improved after annealing. As for the as-deposited and annealed contacts, the specific contact resistivities of 2.886 ? 10-3 and 2.040 ? 10-4 ??cm2 are obtained, respectively. The x-ray photoelectron spectroscopy analysis indicates that the titanium carbide formation occurs at the interface between titanium and the diamond substrate in the as-deposited state, and no TiO2 is observed.