Electrodeposited ceramic single crystals

Single-crystal films are essential for devices because the intrinsic proper ties of the material, rather than its grain boundaries, can be exploited. C ubic 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 degrees to 825 degrees C. The material has not been previously observed at room temperature. Single-crystal films of the high-temperature cubic polym orph of bismuth oxide were epitaxially electrodeposited from an aqueous sol ution onto single-crystal gold substrates. The 35.4 percent lattice mismatc h was accommodated by forming coincidence Lattices in which the bismuth oxi de film was rotated in relation to the gold substrate. These results provid e a method for producing other nonequilibrium phases that cannot be accesse d by traditional thermal processing.