Paulauskas, I. E. and Katz, J. E. and Jellison, G. E. Jr. and Lewis, N. S. and Boatner, L. A. and Brown, G. M. (2009) Growth, Characterization, and Electrochemical Properties of Doped n-Type KTaO_3 Photoanodes. Journal of the Electrochemical Society, 156 (5). B580-B587. ISSN 0013-4651 http://resolver.caltech.edu/CaltechAUTHORS:20090821-130313595
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The effects of compositionally induced changes on the semiconducting properties, optical response, chemical stability, and overall performance of KTaO_3 photoanodes in photoelectrochemical (PEC) cells have been investigated. Single crystals of n-type Ca- and Ba-doped KTaO_3 with carrier concentrations ranging from 0.45 to 11.5×10^(19) cm^(−3) were grown and characterized as photoanodes in basic aqueous electrolyte PEC cells. The PEC properties of the crystals, including the photocurrent, photovoltage, and flatband potential in contact with 8.5 M NaOH(aq) were relatively independent of whether Ca or Ba was used to produce the semiconducting form of KTaO_3. All of the Ca- or Ba-doped KTaO_3 single-crystal photoanodes were chemically stable in the electrolyte and, based on the open-circuit potential and the band-edge positions, were capable of unassisted photochemical H_2 and O_2 evolution from H_2O. The minority-carrier diffusion lengths values were small and comparable to the depletion region width. Photoanodic currents were only observed for photoanode illumination with light above the bandgap (i.e., λ<340 nm). The maximum external quantum yield occurred at λ=255 nm (4.85 eV), and the depletion width plus the minority-carrier diffusion length ranged from 20 to 65 nm for the various KTaO_3-based photoanode materials.
|Additional Information:||©2009 The Electrochemical Society. Submitted 31 July 2008; revised 21 January 2009; published 10 March 2009. This research was sponsored by the Division of Materials Science and Engineering, Office of Basic Energy Sciences, U.S. Department of Energy, under contract no. DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed and operated by UT-Battelle, LLC, and by the Office of Basic Energy Sciences, under grant no. DE-FG0Z-03ERI5483 with the California Institute of Technology. The authors acknowledge, with thanks, the contributions of J. O. Ramey, J. A. Kolopus, and H. E. Harmon to various aspects of this work. University of Tennesse assisted in meeting the publication costs of this article. 82.47.Jk Photoelectrochemical cells, photoelectrochromic cells 82.50.-m Photochemistry 82.45.Fk Electrochemical electrodes 82.45.Gj Electrolytes 72.40.+w Photoconduction and photovoltaic effects 72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping (semiconductors/insulators)|
|Subject Keywords:||barium, calcium, carrier density, carrier lifetime, electrochemical electrodes, electrolytes, energy gap, photoconductivity, photoelectrochemical cells, photoelectrochemistry, photovoltaic effects, potassium compounds, semiconductor materials; PACS: 82.47.Jk, 82.50.-m, 82.45.Fk, 82.45.Gj, 72.40.+w, 72.20.Jv, YEAR: 2009|
|Official Citation:||Growth, Characterization, and Electrochemical Properties of Doped n-Type KTaO[sub 3] Photoanodes I. E. Paulauskas, J. E. Katz, G. E. Jellison, Jr., N. S. Lewis, L. A. Boatner, and G. M. Brown, J. Electrochem. Soc. 156, B580 (2009), DOI:10.1149/1.3089281|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||George Porter|
|Deposited On:||01 Sep 2009 17:10|
|Last Modified:||26 Dec 2012 11:14|
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