Author(s)

Go Sajiki^1*, Yasuhiko Benino², Tokuro Nanba², Hiroshi Okano³

¹Technological, Educational Supporting Center in Takamatsu, Kagawa National College of Technology, Takamatsu, Japan.
²Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
³General Education, Kagawa National College of Technology, Takamatsu, Japan.

Zinc oxide (ZnO) and niobium oxide (NbO_x) with a nano-island structure were deposited by a sputtering method on Al-coated glass substrates. Cells with a (ZnO or NbO_x)/Al/glass|KNO₃aq.|Al/ glass structure were assembled, and electrochemical and photoelectrochemical properties were evaluated. The ZnO and NbOx electrodes had higher electrode potentials than the counter Al/glass electrode, and electron flows from the counter electrode to the ZnO and NbO_x electrodes through the external circuit were commonly confirmed. In the ZnO-based cell, only faint photocurrent generation was seen, where Zn and Al elution from the ZnO electrode was found. In the NbOxbased cell, however, stable generation of electricity was successfully achieved, and electrode corrosion was not recognized even in microscopic observations. A photoelectrochemical conversion model was proposed based on potential-pH diagrams. In the case of nano-island structures formed at shorter NbO_x deposition time, it was concluded that the photoelectrochemical reactions, which were proceeded in the immediate vicinity of the boundary among nano-islands, substrate, and electrolyte solution, were predominant for the photoelectrochemical conversion, and in the case of film structures with longer deposition time, the predominant reactions took place at the film surface.

Nano-Island, Electrochemistry, Photoelectrochemistry, Niobium and Zinc Oxide, Corrosion

Sajiki, G. , Benino, Y. , Nanba, T. and Okano, H. (2015) Electrochemical and Photoelectrochemical Properties of Nano-Islands of Zinc and Niobium Oxides Deposited on Aluminum Thin Film by RF Magnetron Reactive Sputtering. Materials Sciences and Applications, 6, 292-309. doi: 10.4236/msa.2015.64035.