Synthesis of Nitrogen‐Doped Graphene Using Embedded Carbon and Nitrogen Sources

Graphene is the two-dimensional crystalline form of carbon whose extraordinary charge carrier mobility and other unique features hold great promise for nanoscale electronics. [ 1 ] Because graphene has no bandgap, however, its electrical conductivity cannot be completely controlled like classical semiconductor. Theoretical and experimental studies on graphene doping show the possibility of opening the bandgap and modulating conducting types by substituting carbon atoms with foreign atoms. [ 2 ] Graphene is easily p-doped by adsorbates like physisorbed oxygen molecules, but complementary doping (both n-type and p-type doping) is essential for functional device applications like complementary metal-oxidesemiconductor (CMOS) circuits. [ 3 ] Recently, a number of approaches have been proposed to synthesize nitrogen-doped graphene (NG), such as chemical vapor deposition (CVD), [ 2 a, 4 ] arc-discharge, [ 2 b, 5 ] and post treatments. [ 6 ] Here, we report a new approach which makes use of embedded nitrogen and carbon atoms in metal substrate to prepare NG. As doping is accompanied with the combination of carbon atoms into graphene during annealing process, N atoms can be substitutionally doped into the graphene lattice. Our method provides not only a better control over the doping density but also a potential advantage to precisely control the solid dopants at desired locations to achieve patterned doping. Our approach for NG synthesis is actually the enthusiastic utilization of the very common segregation phenomenon to turn the trace amount of carbon and nitrogen dissolved in bulk metals into NG. [ 7 ] Metals usually contain a trace amount of carbon impurities, which could be brought into evaporated metal fi lm during the electron beam deposition process. [7a, 8 ]