Abstract
Diamond nanotips were synthesized on diamond/Si substrates by using a microwave plasma-enhanced chemical vapor deposition process. The diamond nanotips are ∼1 νm in height and the diameter at the bottom of a nanotip is ∼200 nm. The as-grown diamond nanotips exhibit excellent field emission characteristics after treating with nitrogen plasma immersion ion implantation (PIII) for 10 min. A low turn-on field of 3 V νm -1 and a high current density of 4 mA cm -2 at 9 V νm -1 are achieved. The morphologies of diamond nanotips are unchanged after the nitrogen PIII treatment. The diamond quality reduces with treatment time. The sp 3 bonds in diamond can be broken by the nitrogen ions accelerated by the pulse voltage of -25 kV, which results in G peak broadening in Raman spectra. Several nanoscale amorphous regions are generated in a crystalline diamond nanotip, observed by the high resolution transmission electron microscope. The improvement of field emission properties is correlated to the amorphous regions and possible implantation-induced atomic defects. © IOP Publishing Ltd.