UV-irradiation induced defect formation on graphene on metals

- UV-irradiation was done to graphene on a Cu foil in vacuum, nitrogen and ammonia.
- UV-irradiation causes defect formation in graphene independently of ambience.
- UV-irradiation in ammonia enhances defect formation due to a radical reaction.
- Photogenerated radicals play a role in doping of nitrogen atoms to graphene lattice.