Controllable healing of defects and nitrogen doping of graphene by CO and NO molecules

Controllable defect healing and N-doping in graphene would be very valuable for potential device applications. Here we report first-principles molecular-dynamics simulations that suggest a procedure with fast dynamics and low thermal budget. Vacancies can be healed by sequential exposure to CO and NO molecules. A CO molecule gets adsorbed at a vacancy site and a NO molecule subsequently removes the extra O by forming NO2. Controllable N-doping can be achieved by sequential vacancy creation (e. g., by an electron beam) and subsequent exposure to NO molecules at room temperature. A combination of CO and NO molecules can potentially provide simultaneous healing and doping at a desirable ratio. The proposed strategy introduces no extra defects and is promising for graphene-based materials in radiation environments.