Controllable N-Doping of Graphene

Opening and tuning an energy gap in graphene are central to many electronic applications of graphene Here we report N doped graphene obtained by NH3 annealing after N+ ion irradiation of graphene samples First the evolution of the graphene microstucture was investigated following N+ ion irradiation at different fluences using Raman spectroscopy showing that defects were introduced in plane after irradiation and then restored after annealing in N-2 or in NH3 Auger electron spectroscopy (AES) of the graphene annealed in NH3 after irradiation showed N signal however no N signal was observed after annealing in N-2 Last the field effect transistor (FET) was fabricated using N doped graphene and monitored by the source drain conductance and back-gate voltage (G(sd)-V-g) curves in the measurement The transport property changed compared to that of the FET made by intrinsic graphene that is the Dirac point position moved from positive V-g to negative V-g indicating the transition of graphene From p type to n type after annealing in NH3 Our approach which provides a physical mechanism for the introduction of defect and subsequent hetero dopant atoms Into the graphene material in a controllable fashion will be promising for producing graphene based devices for multiple applications