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Ideally ordered anodic porous TiO2 was fabricated by anodizing an Al/Ti layered specimen. A two-layered specimen composed of an Al top layer and a Ti underlying layer was prepared and then processed by nanoimprinting. The Al top layer was easily pretextured by nanoimprinting owing to its softness and it was straightforward to introduce an ideally ordered pore arrangement by anodization. This pore arrangement was transferred to the underlying Ti layer, resulting in ideally ordered porous structures in TiO2. This process can be applied to the high-throughput fabrication of ideally ordered anodic porous oxides other than TiO2 and also to other metals with high hardness. Keywords: Porous TiO2, Anodization, Imprinting process

The influence of atomic hydrogen was investigated using a polycrystalline germanium (poly-Ge) thin-film transistor. High-density-atomic hydrogens were generated by catalytic reaction on a heated W mesh. The defect density in the poly-Ge film and at the poly-Ge/SiO2 interface can be reduced by three orders of magnitude with the passivation ratio of 2.3 × 10−5. From the dependence of treatment time and air exposure time for long time, the defects in poly-Ge films were preferentially terminated in comparison with that at the poly-Ge/SiO2 interface.

Ge thin film is expected as an active layer in a thin-film transistor (TFT) because the electron mobility of Ge is larger than that of Si. In this study, the crystallization of Ge thin film by soft X-ray irradiation and the improvement of interface property of poly-Ge/SiO 2 in poly-Ge TFT by atomic hydrogen annealing (AHA) are investigated for realization of high-performance poly-Ge TFT. The drain current (I d ) did not depend on the gate voltage (V g ) before AHA treatment. However, as the AHA treatment time increased, the I d decreased and the I d came to depend on V g . The on/off ratio of 10 was obtained by AHA for 360 min. It is found that the defect density in poly-Ge film and at poly-Ge/SiO 2 interface can be reduced by AHA slightly.

Ideally ordered TiO2 hole arrays with high aspect ratios were prepared by the anodization of pretextured Ti. The obtained TiO2 acted as two-dimensional photonic crystals in which a photonic band gap is formed in all directions of light propagation in the lattice. The process allows the easy and low-cost fabrication of TiO2 photonic crystals and can be used for the preparation of functional optical devices, which require the precise control of light propagation.