One-step synthesis of tunable nitrogen-doped graphene from graphene oxide and its high performance field emission properties

Simultaneous reduction, repairing and doping of graphene oxide has been realized by the chemical vapor deposition method, using acetonitrile as a nitrogen source. A step-wise increase of acetonitrile partial pressure from 15 to 90 Pa results in nitrogen doped graphene (NG) with gradually tuning N-doping concentration from 0.38 to 0.66 at% and systematically rising graphite-N ratio from 23.25 to 45.39%, which in turn modulates field emission performance and enhance the stability. Raman spectroscopy and X-ray photoelectron spectroscopy suggest pyrrolic-N and pyridinic-N doping bring defects, while defects decrease as N-doping concentration increases due to the rising of graphite-N ratio. Proper defects may increase emission site density and N-doping can reduce work function. When N-doping concentration is controlled at 0.42 at%, NG exhibits the considerable decreasing of turn-on field from 3.35 to 2.18 V/μm at the emission current of 10 μA/cm² and increasing of field enhancement factor from 1835 to 2967. It also reveals a good field emission stability with no degradation, which is superior to pristine reduced GO emitters. It is suggested the NG with tuning concentration of three type nitrogen emitter is a widely candidate for various field emission devices and applications.