Fabrication of Pyramid-Like Structured Cu Coatings by Pulse-Reverse Current Electrodeposition.

Copper (Cu) coatings with a high surface area have attracted significant attention for functional devices due to their high thermal and electrical properties. Pulse-reverse current (PRC) electrodeposition has been introduced to fabricate Cu coatings for a long history, but compared to the individual anodic step, little attention has been paid to the synergistic effects of anodic and cathodic steps. The new parameter “artificial exchange current density” (j_A) has been demonstrated to quantify the effects of anodic and cathodic currents on the morphology in our previous work. Herein, a key metric−the relative current amplitude−that is positively correlated with j_A, is used to further clarify the role of j_A in the electrodeposition process. We fabricate Cu coatings with welldispersed pyramid-like structures and find the relative current amplitude dominates the formation of a larger raised structure at the initial nucleation stage. Moreover, it is speculated that the anodic current can dissolve high-energy planes and achieve a highly (111)-oriented texture. Afterward, screw dislocation drives the spiral growth of grains, resulting in pyramid-like structures. This study not only enriches our understanding of the artificial exchange current density in PRC electrodeposition but also guides us to achieve Cu coatings with high surface area. [ABSTRACT FROM AUTHOR]