Nanoscale imaging of oxidized copper foil covered with CVD‐grown graphene layers

Orientation-dependent oxidation of Cu substrates covered by CVD-grown graphene under ambient conditions has been intensively studied. However, the effect of orientation of graphene layers has been largely overlooked. Here, we reported experimental results on natural oxidation of the polycrystalline Cu substrate coated by partial-coverage CVD-grown graphene stored in dryer under ambient conditions for up to 10 months. SEM, together with AFM, Raman and XPS, was used for systematically studying the morphological and compositional changes at nanoscale during oxidation. Oxidation of the polycrystalline Cu substrate depends sensitively on both orientation of graphene layers and Cu substrates as revealed by the distinctly different morophologies between oxidized and unoxidized regions in SEM images. The time dependence of oxidation for Cu was established. The findings reported here will have important implications for developing protection coatings for Cu.