Epitaxial electrodeposition of orthorhombic alpha-PbO2 on (100)-oriented single crystal Au

Epitaxial films of orthorhombic lead dioxide alpha -PbO2 (Pbcn, a = 0.4971, b = 0.5956, and c = 0.5438 nm) were electrodeposited at room temperature o n a [100]-oriented single crystal Au substrate (cubic, Fm3m, a = 0.4079 nm) . The values of lattice mismatch are 21.9, 46.0, and 33.3% in the a, b, and c directions of alpha -PbO2, respectively. The films are [100]-oriented, w ith the a axis perpendicular to the substrate. Depending on the preparation conditions, the film was found to form two different in-plane orientations , with the unit cell of the PbO2 structure rotated either 45 or 11.5 degree s relative to the substrate. For the films deposited at low current density , only the first type of the in-plane texture is observed, while at high cu rrent densities both types are present in comparable amounts. (C) 2001 The Electrochemical Society. All rights reserved.