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.