Thickness-Dependent Flat Band Potential of Anatase TiO2(001) Epitaxial Films on Nb:SrTiO3(001) Investigated by UHV-Electrochemistry Approach

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• 作者：Yuji Matsumoto ; Yoshihiro Miura ; Shintaro Takata
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：January 28, 2016
• 年：2016
• 卷：120
• 期：3
• 页码：1472-1477
• 全文大小：356K
• ISSN：1932-7455

文摘

The semiconductor characteristics of anatase TiO₂(001) films, which were pulsed laser-deposited on a 0.05 wt % Nb-doped SrTiO₃(001) single crystal electrode, as well as the film/electrolyte heterointerfaces were investigated by the ultrahigh-vacuum electrochemistry approach. In addition to the current–voltage measurements, equivalent circuit modeling in electrochemical impedance spectroscopy at different electrode potentials reveals that the flat band potential of anatase TiO₂ films shifts by +0.5 V when the film thickness increases with (1 × 4) surface reconstruction more visible in reflection high energy electron diffraction. The possible origins of the observed flat band potential shift will be discussed from the viewpoint of electric double layer effects, mainly of donor-type surface states and surface reconstruction, compared with the results of single crystal rutile TiO₂(110).