Nondestructive Characterization of Graphene Defects

An effective method is reported for oxidizing graphene/copper fi lm in which air oxidation of the underlying copper fi lm occurs through the grain boundary lines of graphene without oxidizing graphene. This oxidation is realized by partially immersing the graphene/copper fi lm in sodium chloride solution. Electrons generated during etching of the graphene/copper fi lm in electrolyte diffuse into the fi lm in contact with air, which eventually enhances air oxidation of copper through the graphene layer. While the graphene layer acts as a protective layer against oxidation of the copper fi lm, oxidation of the underlying Cu fi lm near graphene grain boundary lines is observed by optical microscopy. This observation could be attributed to the selective diffusion of oxygen radicals through isolated defects and graphene grain boundaries. The process involves no appreciable oxidation of the graphene layer including the graphene grain boundary, as confi rmed by use of detailed Raman and X-ray photoelectron spectroscopy. DOI: 10.1002/adfm.201300493 T.242611sciescopu