Effect of charge compensation on the photoelectrochemical properties of Ho-doped SrTiO{sub 3} films

Journal Article · Mon Mar 25 04:00:00 EDT 2013 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4798829· OSTI ID:22162809

Zhao, Long; Fang, Liang; Dong, Wen; Zheng, Fengang; Shen, Mingrong ^[1]; Wu, Tom ^[2]

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1. Jiangsu Key Laboratory of Thin Films and Department of Physics, Soochow University, Suzhou 215006 (China)
2. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

When Ho{sup 3+} ions are substituted at Sr{sup 2+} sites in SrTiO{sub 3} (STO), the excess positive charges are compensated via three complementary routes: (1) strontium vacancies, (2) titanium vacancies, and (3) conduction electrons. In this study, we show that the photoelectrochemical properties of Ho-doped STO films are dependent on the charge compensation mechanisms. The compensation mechanism via the titanium vacancies exhibits the highest photocurrent density, which is 1.7 times higher than that of the pure STO sample. Based on the measured dielectric properties and electrochemical impedance spectroscopy data, we propose that the enhanced dielectric constant of the films can enlarge the width of the space charge region at the film/liquid interface, which eventually leads to the increase of the photocurrent density. Further enhancement of photocurrent density is obtained in the samples decorated with appropriate amounts of Pt nanoparticles, showing the advantage of composites for achieving the efficient photoelectrochemical property.

• OSTI ID: 22162809
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 12 Vol. 102; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPOSITE MATERIALS
CRYSTALS
DOPED MATERIALS
ELECTROCHEMISTRY
ELECTRONS
HOLMIUM ADDITIONS
IMPEDANCE
INTERFACES
NANOSTRUCTURES
PERMITTIVITY
PHOTOCONDUCTIVITY
PLATINUM
SPACE CHARGE
SPECTROSCOPY
STRONTIUM TITANATES
THIN FILMS
VACANCIES