Epitaxial Electrodeposition of Orthorhombic α-PbO[sub 2] on (100)-Oriented Single Crystal Au

Epitaxial films of orthorhombic lead dioxide α ­ PbO 2 ( Pbcn , a = 0.4971 , b = 0.5956 , and c = 0.5438 nm) were electrodeposited at room temperature on a [100]-oriented single crystal Au substrate (cubic, Fm 3 m , 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 α ­ PbO 2 , respectively. The films are [100]-oriented, with 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 PbO 2 structure rotated either 45 or 11.5° 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 current densities both types are present in comparable amounts.