Abstract
There are several reports about gas barrier properties of graphene related materials including graphene, graphene oxide and reduced graphene oxide, however stabilities and gas permission mechanisms of graphene related materials have not yet been clarified. In our previous study, O2 molecules gas barrier properties of chemical vapor deposited (CVD) single layer graphene were characterized by using in–situ synchrotron radiation X-ray photoelectron spectroscopy (SR–XPS). A single layer graphene was deposited on Cu (111)/Al2O3 (0001) substrate by thermal CVD method. O2 molecules with kinetic energies between 0.07 and 1.77 eV were irradiated on graphene/Cu (111) samples and oxidizations of Cu surfaces were evaluated by SR–XPS. At low kinetic energies, Cu surfaces were not oxidized. While oxidizations on Cu surfaces were confirmed at high kinetic energies. Interestingly, graphene was not damaged after O2 molecules irradiations regardless of kinetic energies. Based on molecular dynamics-based simulation, it was found that O2 molecules were traveled though divacancy defects in graphene at the high irradiation energies. In case of the low irradiation energies, O2 molecules were bounced off the surface and floated away.
