1. Helium plasma implantation on metals: Nanostructure formation and visible-light photocatalytic response
- Author
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Hisao Yoshida, Naoaki Yoshida, Miyuki Yajima, Yoshitaka Terao, Noriyasu Ohno, Tomoko Yoshida, Daiki Kitaoka, Shin Kajita, and Reo Etoh
- Subjects
Nanostructure ,Materials science ,General Physics and Astronomy ,chemistry.chemical_element ,Nanotechnology ,Tungsten ,chemistry ,Chemical engineering ,Sputtering ,Photocatalysis ,Irradiation ,Plasma processing ,Titanium ,Visible spectrum - Abstract
It has been found recently that low-energy helium (He) plasma irradiation to tungsten (W) leads to the growth of W nanostructures on the surface. The process to grow the nanostructure is identified as a self-growth process of He bubbles and has a potential to open up a new plasma processing method. Here, we show that the metallic nanostructure formation process by the exposure to He plasma can occur in various metals such as, titanium, nickel, iron, and so on. When the irradiation conditions alter, the metallic cone arrays including nanobubbles inside are formed on the surface. Different from W cases, other processes than growth of fiberform structure, i.e., physical sputtering and the growth of large He bubbles, can be dominant on other metals during irradiation; various surface morphology changes can occur. The nanostructured W, part of which was oxidized, has revealed a significant photocatalytic activity under visible light (wavelength >700 nm) in decolorization of methylene blue without any co-catalyst.
- Published
- 2013