This paper demonstrates the impacts of light and ambient gas on the resistance of sputter-deposited non-doped ZnO films. Although the authors have already demonstrated the impact of light from various LEDs with a different wavelength on the resistance of such films, key results were not shown in detail. In this paper, the influence of ambient gas on the resistance and the influence of temperature on resistance are demonstrated in detail, and feasible physics drawn from analysis results are discussed. Physical images of the phenomena are proposed. It is also comprehensively revealed that the film surface condition significantly contributes to the transport characteristics of the film; this is supported by the impact of ambient gas in the dark on the current decay process in the film.
For the waveguide having a pillar-missing-line defect in a photonic crystal (PhC) with dielectric pillars in air, a pillar-missing-line defect can support the low-loss transmission when the mode frequency falls inside the photonic bandgap (PBG). In this paper, the waveguide with the single-missing-hole-line defect in the silicon on insulator (SOI) PhC slab, which has square air holes in silicon on a square array, is studied by the FDTD simulation. It seems that even in this structure, a high transmission coefficient is obtained in the bandgap-guided mode. However, a low-loss transmission was observed at outside the PBG. This is the propagation of the index-guided mode based on the refractive index of the core being larger than average index of the cladding medium. Appropriately, choosing the design parameters (the silicon core is 1000-nm thick, lattice constant is 500-nm, and air hole size is 250-nm square), we find that the present PhC has a TE gap ranging from 95-THz to 135-THz. These values approximately agree with the 2D theoretical gap ranging from 92-THz to 133-THz because the silicon layer is thick. The low-loss transmissions are obtained at the frequencies outside the PBG in the longitudinal and transverse directions except for the low-loss transmission frequency in the oblique direction on the original PhC. This is the propagation of the index-guided mode. Since the omni-directional bandgap of PhC with a square lattice is generally smaller than that for a triangular lattice, it is considered that PhC with the square lattice is unsuitable to forming sharp waveguide bends. However, in this paper, we propose the fundamental structure of a ring resonator with sharp U-turns such that the possibility of obtaining a high Q value can also be expected. Assuming a 300-nm-thick silicon layer, the 420-nm lattice constant and 300-nm square air holes, we find good optical confinement near 210-THz. At the resonance of 211-THz, we obtain the Q-value of 100 from the saturated tuning curve in the limit to the Fourier transform. These facts indicate that the resonator with sharp U-turns has Q value greater than 100. Since the leakage to the lower and upper layers is not considered in the present study, the possibility of obtaining a high Q value can also be expected.