Field Emission Properties Of Carbon Research Articles

Using copper substrate to enhance electron field emission properties of carbon nanotube/diamond double-layered structure

Vertically aligned carbon nanotube (CNT)/diamond double-layered structure was synthesized on copper (Cu) substrate by hot-filament chemical vapor deposition. The structure was characterized by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The results show that the diamond layer has good adhesion to the Cu substrate and the CNTs have direct contact with the diamond layer. Field electron emission measurement shows that the double-layered structure on copper has very good emission stability and a much lower turn-on field than that on silicon (Si).

First-principles investigation of the electronic and field emission properties of C-doped ZnO nanotube

In order to search for novel field emitter nanomaterial, a density functional theory investigation is performed to understand electronic structures and field emission properties of carbon doped–ZnO nanotube. It has been revealed that electron transport through ZnONT is significantly increased in the presence of the carbon atom due to the reduced HOMO–LUMO energy gap, which makes the electrons easily excited from HOMO to LUMO, and then the electrons can easily emit. Comparing the ionization potentials of the pure and doped ZnONT, at the same external electric field strength, the ionization potential of C–doped ZnO nanotube is lower than that of pure one. Also, after the doping of carbon atom, the Fermi level of ZnONT increases, which indicates that the Fermi level shifts toward the conduction band. These results indicate that the field emission properties of ZnONT can be enhanced by the doping of ZnO nanotube with the carbon atom.

Influence of the growth temperature on structural and electron field emission properties of carbon nanowall/nanotube films synthesized by catalyst-free PECVD

Nanocrystalline graphite films composed of carbon nanowalls and cone-shaped carbon nanotubes have been synthesized without the use of any catalyst by means of plasma enhanced chemical vapor deposition in the plasma of direct current glow discharge. The effect of growth temperature on the structural and field emission properties of the nanocrystalline graphite films has been studied. It was demonstrated that variation of the surface temperature during plasma synthesis dramatically affects carbon nanowall and nanotube structural features. Moreover, higher growth temperature results in higher stability of the electron field emission properties of nanocrystalline graphite films.

Deep reactive ion etching as a tool for nanostructure fabrication

Deep reactive ion etching (DRIE) is investigated as a tool for the realization of nanostructures and architectures, including nanopillars, silicon nanowires or carbon nanotubes on Si nanopillars, nanowalls, and nanonetworks. The potential of combining top-down fabrication methods with the bottom-up synthesis of one-dimensional nanocomponents is assessed. The field-emission properties of carbon nanotubes/Si pillars hybrid structures are measured, as well as the transport properties of large-area nanowires obtained via nanowire lithography. The potential of DRIE for the fabrication of three-dimensional nanostructures is also revealed.

Field emission properties of carbon coated Si nanocone arrays on porous silicon

Silicon nanocone arrays are formed on porous silicon substrates by plasma etching in a hotfilament chemical vapour deposition system. The as-formed Si nanocones werecharacterized by means of scanning electron microscopy, high resolution transmissionelectron microscopy, energy dispersive x-ray analysis, and Raman spectroscopy. The resultsindicate that the nanocone is composed of a silicon core coated with a thin amorphouscarbon (a-C) layer produced by carbon-bearing plasma etching. Plasma etching is a keyfactor in the formation of the nanocone arrays, while re-condensation of evaporated siliconatoms on the tip of the as-etched cone also occurs. Field emission measurementsshow that the a-C coating can effectively enhance the field emission ability of thenanocone arrays due to the decrease of the surface work function from 4.15 to 2.37eV.

Synthesis and field emission properties of carbon nanotubes/nanofibers grown on pyrolyzed polyaniline–SiO2 substrates

Pyrolyzed polyaniline–SiO2 substrates with the rough surface containing some holes were prepared by the pyrolysis of polyaniline–SiO2 composites at temperature of 900 °C. Carbon nanotubes/nanofibers (CNTs/CNFs) were grown on the rough surface and inside the holes using a CVD method with a xylene–ferrocene mixture as a carbon and catalyst precursor source. The structural and morphological properties of CNTs were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that the SiO2 content of the substrates was responsible to the diameter and electron field emission properties of CNTs.