Electrodeposited Ceramic Single Crystals
Single-crystal films are essential for devices because the intrinsic properties of the material, rather than its grain boundaries, can be exploited. Cubic bismuth oxide has the highest known oxide ion mobility, which makes it useful for fuel cells and sensors, but it is normally only stable from 729° to 825°C. The material has not been previously observed at room temperature. Single-crystal films of the high-temperature cubic polymorph of bismuth oxide were epitaxially electrodeposited from an aqueous solution onto single-crystal gold substrates. The 35.4 percent lattice mismatch was accommodated by forming coincidence lattices in which the bismuth oxide film was rotated in relation to the gold substrate. These results provide a method for producing other nonequilibrium phases that cannot be accessed by traditional thermal processing.
J. A. Switzer, "Electrodeposited Ceramic Single Crystals," Science, American Association for the Advancement of Science (AAAS), Apr 1999.
The definitive version is available at http://dx.doi.org/10.1126/science.284.5412.293
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© 1999 American Association for the Advancement of Science (AAAS), All rights reserved.