Long Term Anti-Corrosion Effect of Nitrogen-Doped Amorphous Carbon Film on Transparent and Deformable Ultrathin Copper Film

For transparent and deformable electronics, ultrathin metal film has been considered as a promising candidate due to its transparency and flexibility. But oxidation and corrosion problems of metal films inevitably cause degradation in conductivity and device performance. To overcome these problems, many studies have applied passivation layers on metal films as a barrier between air/water and metal. This study presents that the top copper (Cu) layer can have a significant anti-corrosion effect despite the N-doped amorphous carbon (a-C) film being underneath the metal layer. In addition, the ultrathin Cu layer grown on the a-C film shows an enhanced conductivity compared to the bare Cu layer. The main cause of corrosion protection and conductivity enhancement of Cu on the a-C film is nitrogen in the a-C film, which interacts with Cu atom electrically. Also, the Cu layer on the a-C film shows high transmittance over 80%. We systemically analyze the mechanism of the underlying a-C film to reduce the resistance of the top Cu film and prevent long-term corrosion.