Cobalt Oxide (Co3O4) Thin Films Synthesized by Atmospheric Pressure PECVD: Deposition Mechanisms and Catalytic Potential

Abstract

Crystalline and electrocatalytically active cobalt oxide (Co₃O₄) thin films were successfully synthesized under open-air conditions using atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) with the Co(acac)₃ precursor. This study explored the influence of process parameters on the composition, crystallinity, and quality of the resulting thin films. It was found that the substrate temperature had a negligible effect due to the inherent heating by the plasma afterglow. The presence of atmospheric oxygen was identified as crucial for forming Co₃O₄ thin films and eliminating residual impurities such as carbon and nitrogen, as demonstrated by experiments in O₂-free environments. The formation of Co₃O₄ was attributed to radical-mediated reactions, where the reactive species generated in the plasma interacted with oxygen-rich molecules from the surrounding air. These findings provide valuable insights into the deposition mechanisms and catalytic potential of Co₃O₄ thin films synthesized via AP-PECVD.