Nitrogen Incorporated Highly Aligned Carbon Nanotube Arrays Thin Film Grown from Single Feedstock for Field Emission

Vertically aligned nitrogen doped carbon nanotube arrays with uniform height were synthesized on silicon wafer by pyrolyzing the acetonitrile–ferrocene mixture by injection chemical vapor deposition process. The morphology/structure and crystallinity of the as-grown carbon nanotubes were characterized by scanning electron microscopy, transmission electron microscopy (TEM) and Raman spectroscopy. TEM micrographs showed bamboo like morphology of graphene layers in series of compartments. X-ray photoelectron spectroscopy was used to analyze the nitrogen concentration in carbon nanotubes and it was observed that the nitrogen content in nanotubes was around 12.3 atomic%. Field emission study of as-grown nitrogen-doped carbon nanotubes suggests that they are good emitters with a turn-on and threshold field of 0.6 V/μm and 1.6 V/μm respectively. The maximum current density was observed to be 18.8 mA/cm² at 2.1 V/μm. It is considered that the good field emission characteristics of doped nanotube is due to the presence of lone pairs of electrons on nitrogen atom that supplies more electrons to the conduction band.