Structure of thin lead oxide layers as determined by x-ray diffraction

Thin lead oxide layers (30-80 Å thick) %were grown on evaporated lead films using both thermal oxidation and rf oxygen plasma oxidation. These layers were characterized structurally, using x-ray diffraction in the standard Bragg-Brentano configuration. The layers were crystalline orthorhombic PbO with a very strongly preferred (001) orientation parallel to the {111} preferred orientation in the evaporated Pb films. Thickness and strain were determined from line broadening and peak shift, and the strain as a function of thickness is explained using a simple dislocation model for the structure of the lead-lead oxide interface. The high-temperature orthorhomic phase observed may be stabilized by epitaxial forces.