Model Evaluations of Surface Modification by Energetic Incident Carbon Atoms on Graphene Coated Copper Electrodes

Thin nanoscale coating of metal electrodes by graphene promises to be a useful approach<br>for suppressing secondary electron yield and potential multipactor. Recent calculations showed<br>reductions by as much as 50 percent for graphene over copper electrodes for energies below 125<br>eV, with results in good agreement with experimental data. Here the resistance to possible<br>degradation of this structure, in response to incoming atomic projectiles, is gauged based on<br>Molecular Dynamics simulations. Our results for surface irradiation by carbon atoms (as an<br>example) on nanoscale graphene coatings indicate a defect threshold of about 35 eV, lower surface<br>damage for thicker layers, negligible sputtering, and defects less than 6 Angstroms in dimension<br>for energies up to 300 eV. The electrode structure is shown to be robust with better resistance to<br>damage than metal alone.