Structure and Composition of Cu_2O Films Produced by Anodizing Copper Foil on Fiberglass Laminate

摘要

The effect of process conditions on the composition and structure of anodic Cu_2O films grown in sulfate-chloride electrolytes has been studied using Auger electron spectroscopy, x-ray diffraction, and atomic force microscopy. The results demonstrate that the copper and oxygen depth profiles in the anodic copper(I) oxide films (ACOFs) are similar in shape. The copper content near the surface is only slightly lower than the bulk copper content. Starting at a depth of 9 nm, the Cu content is constant at an average of 62.7 at %. The Cu_2O films grown at a current density j = 3 mA/cm~2 have the most perfect stoichiometry, with deviations only in the surface layer. Anodic oxidation produces unoriented polycrystalline films of complex composition. In addition to Cu_2O, the films contain CuCl and trace levels of copper. Raising the anode current density influences, for the most part, the formation of (111 )-oriented crystallites, changing their orientation from (111) to (220). We assume that nonmetal (oxygen or chlorine) atoms are incorporated into the cubic structure of copper without changing its symmetry but increasing its unit-cell parameter: from 0.3607 (Cu) to 0.426 (Cu_2O) and to 0.541 nm (CuCl).