Study on electron field emission enhancement from nitrogenated carbon nanotips synthesized by plasma-enhanced hot filament chemical vapor deposition

Nitrogenated carbon nanotips (NCNTPs) with different structures were synthesized by plasma-enhanced hot filament chemical vapor deposition using methane, hydrogen and nitrogen as the reactive gases. The structures and compositions of the NCNTPs were studied by field emission scanning electron microscopy (FESEM), micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The XPS spectra reveal that nitrogen is incorporated into the carbon nanotips to form the NCNTPs under plasma condition. The Raman spectra and FESEM images show that the NCNTPs are amorphous structure and their morphologies change with the change in deposition conditions, respectively. The electron field emission (EFE) from the NCNTPs was measured and the EFE results indicate that the NCNTPs with the smooth surfaces and high density can emit a current density of 3 × 10³ μA/cm² at an electric field of 7.2 V/μm, which exhibits better EFE characteristic than the NCNTPs with the carbon nanowires on their surfaces due to small amount of oxygen adsorbed on the smooth surfaces of NCNTPs. According to the possible structures of nitrogen in sp² cluster in rings, the EFE enhancement of the NCNTPs compared with pure carbon nanotips was studied. The high emission current density (3 × 10³ μA/cm²) at low field (7.2 V/μm) suggests that the NCNTPs can serve as effective electron emission sources for numerous applications.