Electrical and mechanical performance of graphene sheets under oxidative environments
Huiling Duan (Peking University)
Prager Medal Symposium in honor of George Weng: Micromechanics, Composites and Multifunctional Materials
Tue 9:00 - 10:30
MacMillan 117
Graphene can be a suitable passivating layer that protects the underlying material from oxidation in hydrogen peroxide (H2O2, room temperature) and air atmospheres (up to 200 ºC). In this work, we observe that domain boundaries of graphene on copper can also act as local centers for oxygen accumulation when keeping the samples in air atmosphere at room temperature for long periods of time (from 1 day to 113 days). We compare the performance of graphene/Cu stacks in both H2O2 and air atmosphere using Scanning Electron Microscope, Conductive Atomic Force Microscope and Auger Electron Microscope analyses. We observe that unlike the graphene sheets exposed to H2O2, in which the accumulation of oxygen at the graphene domain boundaries evolves in a very controlled and progressive way, the local oxidation of the graphene in air atmospheres happens in a disordered way. In both cases the oxide hillocks formed at the graphene domain boundaries can propagate to the domains until reaching a limit width and height. Our results point out that local oxidation of the underlying material along the graphene domain boundaries can dramatically impoverish the roughness, conductivity, mechanical resistance and frictional characteristics of the graphene sheet, which reduces the performance of the whole device.