A new and simplified method of fabricating anodic aluminum oxide has been developed. This new method uses anodization but follows a route different from the commonly known 1-or 2-step anodization. General-purity (99.7%) commercial aluminum is used instead of the high-purity aluminum required in conventional anodization. The disordered arrangements of pores that initially form on the surface of aluminum rearranged by self-diffusion inside the anodic aluminum oxide (AAO) layer via long-term heat treatment. The enlargement of the pores on AAO that crystallized to phase was achieved by pore widening. Uniformly distributed nanopores with a diameter of 75 nm and wall a thickness of 16 nm were formed on a 9 mm thick AAO film. These ordered nanochannels were obtained over an area of several square millimeters, with a density of 1:4 Â 10 10 pores per cm 2 .

Tin (Sn) nanowires, with 15 and 60 nm average diameter and up to 10 µm in length, were fabricated by an injection process using a hydraulic pressure method. The Sn melt was injected into an anodic aluminium oxide (AAO) template and solidified to form nanowires. By back etching the aluminium substrate and barrier layer, the nanowire array ends were partially exposed from the bottom face of the AAO template. The filling ratio of nanowires inside and through the thickness of the AAO template was found to be close to 100%. The nanowires were also found to be dense and continuous with uniform diameter throughout their length. Transmission electron microscope (TEM) and x-ray diffraction (XRD) studies on the 60 nm diameter nanowires revealed that the nanowires were single crystals with body-centred-tetragonal (bct) structure predominantly growing along the [100] direction. The current method of synthesizing nanowires is straightforward, low-cost and suitable for low-melting point (<650 °C) metals including low-melting point alloys with stoichiometric composition.

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This paper concerns the microstructure of the anodic titanium oxide ͑ATO, TiO 2 ͒ nanotube ͑NT͒ and its use for the dye-sensitized solar cell ͑DSSC͒ device. The ATO length was controlled by various electrolytes and anodic time at various constant applied voltages. The lengths of the NTs at 0.3-0.5 and 0.9-22 m were controlled by 0.5 vol % HF and 0.58 wt % KF aqueous solutions for varied periods of anodization ͑1-24 h͒. The 0.5 wt % NH 4 F electrolyte in ethylene glycol can produce 4-41 m for varied periods of anodization ͑0.5-8 h͒. ATO made of 0.3 ͑0.5 vol % HF͒, 12 ͑0.5 wt % KF͒, and 18 m ͑0.5 wt % NH 4 F͒ was used for the DSSC anode; the best cell performance attained 0.13, 3.76, and 6.18%. The DSSC made of 18 m ATO has a short-circuit current density ͑J sc ͒ of 13.45 mA/cm 2 , a fill factor of 0.64, an open voltage ͑V oc ͒ of 0.72 V, and a photocurrent efficiency of 6.18% under an air mass 1.5 illumination test.

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