TITLE:
Electrochemical and Photoelectrochemical Properties of Nano-Islands of Zinc and Niobium Oxides Deposited on Aluminum Thin Film by RF Magnetron Reactive Sputtering
AUTHORS:
Go Sajiki, Yasuhiko Benino, Tokuro Nanba, Hiroshi Okano
KEYWORDS:
Nano-Island, Electrochemistry, Photoelectrochemistry, Niobium and Zinc Oxide, Corrosion
JOURNAL NAME:
Materials Sciences and Applications,
Vol.6 No.4,
April
8,
2015
ABSTRACT: Zinc oxide (ZnO) and niobium oxide (NbOx) with a nano-island structure were deposited by a
sputtering method on Al-coated glass substrates. Cells with a (ZnO or NbOx)/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 NbOx 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 NbOx 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.