Air-stable n-type doping of graphene from overlying Si3N4 film

Abstract

• Air-stable n -type graphene was obtained by depositing Si 3 N 4 film on graphene. • The overlying Si 3 N 4 film can cause an effective n -type doping of graphene. • The Dirac point of graphene can be modulated by the thickness of Si 3 N 4 film. In this study, we report a facile method to obtain air-stable n -type graphene by plasma-enhanced chemical vapor depositing Si 3 N 4 film on the surface of graphene. We have demonstrated that the overlying Si 3 N 4 film can not only act as the penetration-barrier against H 2 O and O 2 adsorbed on the graphene surface, but also cause an effective n -type doping due to the amine groups at the interface of graphene/Si 3 N 4 . Furthermore, the studies reveal that the Dirac point of graphene can be modulated by the thickness of Si 3 N 4 film, which is due to competing effects of Si 3 N 4 -induced doping ( n -type) and penetrating H 2 O (O 2 )-induced doping (p-type). We expect this method to be used for obtaining stable n -type graphene field-effect transistors in air, which will be widely used in graphene electronic devices.