Preparation And Characterization Of Carbon Nitride Nanotips By CVD

Owing to unique structure, excellent mechanical and electronic properties ofCNTPs, they have great potential application in the field of optoelectronic devices andmicroelectronic devies. However, appropriate doping can change the electronicstructure of the materials, thus change the properties of materials. This work wascarried out to study through the preparation of nitrogen carbon nanotis doped nitrogenand preparation and properties of nitrogenated carbon nanotips （NCNTPs）.Nitrogenated carbon nanotips of the different structure were prepared on siliconsubstrate in plasma-enhanced hot filament chemical vapor deposition system, in whichmethae, hydrogen and nitrogen were used as the reaction gases. The morphologies,structures and compositions of carbon nitrde nanotips were studied by Hitachi S-4800field emission scanning electron microscopy, Renishaw micro-Raman spectroscopyand X-ray photoelectron spectroscopy, respectively, and the electron field emission（EFE） of the NCNTPs was measured.FESEM images show that the morphology of the NCNTPs prepared underdifferent conditions change with the change of the deposition conditions （such as theratio of etching gas （N₂:H₂），the flow of carbonaceous gas （CH₄）, the working pressure,the bias current, temperature, deposition time）. When the ratio of the etching gas（N₂:H₂）, the flow of CH₄, the working pressure, the bias current （Ib）, temperature, thedeposition time is1:7,20sccm,2KPa,180mA,800℃,20min, respectively, the aspectratio, density and uniformity of the NCNTPs are best. With increases of the etching gas（N₂:H₂） or the flow of CH₄, the growth of the NCNTPs is more disadvantageous. Theincrease or decrease of the working pressure is not conducive to the growth of theNCNTPs, too. The NCNTPs are continuous growth with the increases of the biascurrent （Ib）. With the rise of the deposition temperature （T） or the deposition time, theheight, bottom width and top diameter of the NCNTPs increases, respectively. Whenthe temperature is abve800℃or the deposition time is more than20min, the NCNTPsis no longer grow.XPS spectra and Raman spectra show that the prepared the nitrogened carbonnanotips is amorphous carbonitride structure consisting of sp³C-C、sp³C-N、sp²C-Cand sp²C-N, the amorphous phase is sp³C-C、sp³C-N、sp²C-C and sp²C-N. Theelectron field emission （EFE） characteristics show the electron field emission of NCNTPs is related to its morphology and structure. The NCNTPs with the smoothsurfaces and high density have a better electron field emission than the NCNTPs ofrough surfaces and low density. When the electric field is7.2V/μm, the NCNTPs withsmooth surfaces and high density can emit a current density of3×10³μA/cm². Theprepared NCNTPs are carbonitride structure and the work function of electron can bereduced by the in corporation of nitrogen. Thus, the NCNTPs have better EFEcharacteristic than the pure carbon nanotips.