Dynamic force microscopy and X-ray photoemission spectroscopy studies of nanowire fabrication on a highly oriented line-structure of Al surface

Kato, Hitoshi; Watanabe, Yohei; Takemura, Susumu; Nakano, Ryu; Sugiyama, Takeharu; Shimada, Kazuhiro; Hiramatsu, Tomoyasu; Nanba, Noriyuki; Matsui, Kazunori Japan

Nanowire fabrication was implemented on the nanoscale highly-oriented line-structure of Al surface. An Al plate was chemically and electrochemically processed by applying DC voltage in H2SO4 solution in order to fabricate a nanoscale highly-oriented line structure on the surface. At the first stage, the Al surface was treated with an acetone cleansing process under supersonic. The dynamic force microscopy (DFM) image of the acetone treated surface showed that line-shaped grooves with randomly various widths could be observed. Successive electrochemical process triggered forming finer nanostructures on the surface. The DFM measurement clarified that the nanoscale highly-oriented line-structure was created on the Al surface by the successive electrochemical process. The line width was estimated under 50 nm by the cross section analysis. Aniline monomer solved in pure water and oxidizing agent APS solved in HCl successively dropped on the nanostructure as a droplet and were extended on the surface. The solution conditions were determined by the preliminary experiment on aniline polymerization in a test tube. Aniline monomer was polymerized in a test tube under those conditions. In that case, among the polyaniline structures such as Luecoemeraldine (LE), Pernigraniline (PE) and the mixed-type Emeraldine base (EB), the polymerized polyaniline was the mixed type EB which turned blue. The DFM observation and the cross section analysis were conducted on pre-deposited and deposited surfaces. The DFM cross section analysis clarified that the line-structure still remained and the depth of the row became shallow after the polymerization process was applied by dropping APS on the surface. N 1s core-level lines appeared after the aniline polymerization by X-ray photoemission spectroscopy (XPS) measurements. The C 1s spectrum which originated from the polyaniline backbone was composed of two peaks. Thus, the aniline monomers were polymerized along the line and filled in the row channel. Spectral profiles of each core level peak reflected the polymerization and the polymer-surface binding states.

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