Thermal Transport During Nanoscale Machining by Field Emission of Electrons from Carbon Nanotubes

2003 ◽  
Vol 125 (4) ◽  
pp. 546-546 ◽  
Author(s):  
C. Trinkle ◽  
P. Kichambare ◽  
R. R. Vallance ◽  
B. Sadanadan ◽  
A. M. Rao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Field Emission ◽  
Thermal Transport ◽  
Field Emission Of Electrons

scholarly journals Effect of heating and resistance on emission properties of carbon nanotubes

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Sergey V. Bulyarskiy 1 ◽  
Alexander A. Dudin 1 ◽  
Alexander V. Lakalin 1 ◽  
Andrey P. Orlov 1 ◽  
Alexander A. Pavlov 1 ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Field Emission ◽  
Thermionic Emission ◽  
Negative Resistance ◽  
Cvd Method ◽  
Field Emission Current ◽  
Multi Walled Carbon Nanotube ◽  
Voltage Current Characteristic ◽  
Field Emission Of Electrons ◽  
A Current

We have studied the effect of the series resistance on the heating of the cathode, which is based on carbon nanotubes and serves to realize the field emission of electrons into the vacuum. The experiment was performed with the single multi-walled carbon nanotube (MCNT) that was separated from the array grown by CVD method with thin-film Ni-Ti catalyst (nickel 4 nm / Ti 10 nm). The heating of the cathode leads to the appearance of a current of the thermionic emission. The experimental voltage current characteristic exhibited the negative resistance region caused by thermal field emission. This current increases strongly with increasing voltage and contributes to the degradation of the cold emitter. The calculation of the temperature of the end of the cathode is made taking into account the effect of the phenomenon that warms up and cools the cathode. We have developed a method for processing of the emission volt-ampere characteristics of a cathode, which relies on a numerical calculation of the field emission current and the comparison of these calculations with experiments. The model of the volt-ampere characteristic takes into account the CNT’s geometry, properties, its contact with the catalyst; heating and simultaneous implementation of the thermionic and field emission. The calculation made it possible to determine a number of important parameters, among which the voltage and current of the beginning of thermionic emission, the temperature distribution along the cathode, the resistance of the nanotube. The phenomenon of thermionic emission from CNT’s was investigated experimentally and theoretically. The conditions of this type emission occurrence were defined. The results of the study could form the basis of theory of CNT emitter’s degradation.

scholarly journals Field Emission Properties of Carbon Nanotubes with Boron Doping and H2O Adsorption

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Yijun Wang ◽  
Liuding Wang ◽  
Cheng Yan
Keyword(s):  
Carbon Nanotubes ◽  
Field Emission ◽  
Boron Atom ◽  
Gas Adsorption ◽  
Mulliken Charge ◽  
Electronic Density ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Electron Field ◽  
Field Emission Of Electrons

Gas adsorption and atom doping usually present when preparing carbon nanotubes (CNTs) and can affect the field emission properties of carbon nanotubes. H2O molecule and boron atom are the most important adsorbates, respectively. Using ab-initio calculations, we have investigated the electron field emission performance of CNTs simultaneously adsorbed with one H2O molecule and doped with one boron atom (BCNT+H2O) in this paper. The results indicate that the electrons localize at the top of BCNT+H2O and the electronic density of states (DOS) around the Fermi level is enhanced obviously. It is expected that BCNT+H2O will be more propitious to the field emission of electrons based on the calculations of DOS, HOMO/LUMO, and Mulliken charge population.

Effect of adsorbates on field emission from flame-synthesized carbon nanotubes

2008 ◽  
Vol 41 (19) ◽  
pp. 195401 ◽  
Author(s):  
Chun Li ◽  
Guojia Fang ◽  
Xiaoxia Yang ◽  
Nishuang Liu ◽  
Yuping Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Field Emission

scholarly journals A Thermal Transport Study of Branched Carbon Nanotubes with Cross and T-Junctions

2021 ◽  
Vol 11 (13) ◽  
pp. 5933
Author(s):  
Wei-Jen Chen ◽  
I-Ling Chang
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Thermal Management ◽  
Thermal Transport ◽  
Topological Defects ◽  
Branch Length ◽  
Phonon Transport ◽  
Heat Current ◽  
Transport Mechanisms ◽  
Non Equilibrium Molecular Dynamics

This study investigated the thermal transport behaviors of branched carbon nanotubes (CNTs) with cross and T-junctions through non-equilibrium molecular dynamics (NEMD) simulations. A hot region was created at the end of one branch, whereas cold regions were created at the ends of all other branches. The effects on thermal flow due to branch length, topological defects at junctions, and temperature were studied. The NEMD simulations at room temperature indicated that heat transfer tended to move sideways rather than straight in branched CNTs with cross-junctions, despite all branches being identical in chirality and length. However, straight heat transfer was preferred in branched CNTs with T-junctions, irrespective of the atomic configuration of the junction. As branches became longer, the heat current inside approached the values obtained through conventional prediction based on diffusive thermal transport. Moreover, directional thermal transport behaviors became prominent at a low temperature (50 K), which implied that ballistic phonon transport contributed greatly to directional thermal transport. Finally, the collective atomic velocity cross-correlation spectra between branches were used to analyze phonon transport mechanisms for different junctions. Our findings deeply elucidate the thermal transport mechanisms of branched CNTs, which aid in thermal management applications.

scholarly journals Residual Gas Adsorption and Desorption in the Field Emission of Titanium-Coated Carbon Nanotubes

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2937 ◽  
Author(s):  
Huzhong Zhang ◽  
Detian Li ◽  
Peter Wurz ◽  
Yongjun Cheng ◽  
Yongjun Wang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Gas Adsorption ◽  
Mass Spectrometry Analysis ◽  
Emission Characteristic ◽  
Spectrometry Analysis ◽  
Pristine Cnts ◽  
Xps Characterization ◽  
Residual Gas

Titanium (Ti)-coated multiwall carbon nanotubes (CNTs) emitters based on the magnetron sputtering process are demonstrated, and the influences of modification to CNTs on the residual gas adsorption, gas desorption, and their field emission characteristic are discussed. Experimental results show that Ti nanoparticles are easily adsorbed on the surface of CNTs due to the “defects” produced by Ar+ irradiation pretreatment. X-ray photoelectron spectroscopy (XPS) characterization showed that Ti nanoparticles contribute to the adsorption of ambient molecules by changing the chemical bonding between C, Ti, and O. Field emission of CNTs coated with Ti nanoparticles agree well with the Fowler–Nordheim theory. The deviation of emission current under constant voltage is 6.3% and 8.6% for Ti-CNTs and pristine CNTs, respectively. The mass spectrometry analysis illustrated that Ti-coated CNTs have a better adsorption capacity at room temperature, as well as a lower outgassing effect than pristine CNTs after degassing in the process of field emission.

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