Field Emission Properties of Large Area Carbon Nanotube Cathodes in DC and Pulse Modes

2008 ◽  
Vol 1081 ◽  
Author(s):  
Qingliang Liao ◽  
Yue Zhang ◽  
Liansheng Xia ◽  
Junjie Qi ◽  
Yunhua Huang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Electric Field ◽  
Field Emission ◽  
Direct Current ◽  
Current Density ◽  
Emission Current Density ◽  
Pulse Mode ◽  
Emission Current ◽  
Large Area ◽  
Emission Properties

AbstractA large area carbon nanotube cathode was fabricated by use of a screen printing method. The emission properties of the cathode were investigated in both direct current and pulse mode experiments. In the direct current mode, the cathode has high field enhancement factor and high emission current density. In the double-pulse mode, the emission current density can approach 267 A/cm2 at an applied electric field of 15.4 V/um. Steady intense electron beams were obtained from the cathode. The results proved that the emission mechanism of CNTs at pulse electric field is plasma-induced field emission. The carbon nanotube cathode is suitable for not only field emission display applications but also high-power microwave device applications.

scholarly journals Micro Flowers of SrS/Bi2S3 Nanocomposite and Its Field Emission Properties

2019 ◽  
Vol 3 (4) ◽  
pp. 105
Author(s):  
Aarti R. Gunjal ◽  
Ujjwala P. Chothe ◽  
Yogesh A. Sethi ◽  
Rajendra P. Panmand ◽  
Jalinder D. Ambekar ◽  
...  
Keyword(s):  
Field Emission ◽  
Current Density ◽  
Emission Current Density ◽  
Emission Current ◽  
Threshold Field ◽  
Light Illumination ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Morphological Studies ◽  
A Current

The three-dimensional hierarchical SrS/Bi2S3 heterostructures were synthesized by a template-free single-step hydrothermal method. The structural and morphological studies revealed the formation of a single crystalline orthorhombic heterostructure with rod-like morphologies possessing a high aspect ratio. The field emission properties of SrS/Bi2S3 nanorods were investigated. J–E and the Fowler–Nordheim (F–N) plot, as well as long-term field emission (FE) stability, were studied. SrS/Bi2S3 nanoflowers have enhanced the FE properties more than the virgin Bi2S3. The observed values of the re-producible turn-on field for SrS/Bi2S3 defined to draw an emission current density of ca. 1 µA/cm2 were found to be ca. 2.50 V/µm, and of the threshold field to draw a current density of ca. 10 µA/cm2 were found to be ca. 3.00 V/µm (without visible light illumination). A maximum emission current density of ca. 527 μA/cm2 was drawn without light and a current density of ca. 1078 μA/cm2 with light, which is higher than that of pristine Bi2S3.

Growth of Carbon Nanofibers on Electroless Ni-P Alloy Catalyst

2002 ◽  
Vol 740 ◽  
Author(s):  
T.K. Tsai ◽  
W.L. Liu ◽  
S.H. Hsieh ◽  
W.J. Chen
Keyword(s):  
Field Emission ◽  
Current Density ◽  
Small Diameter ◽  
Emission Current Density ◽  
Emission Current ◽  
Threshold Field ◽  
Random Orientation ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Electroless Ni

ABSTRATECarbon nanotubes (CNTs) were grown by electroless Ni-P plated on silicon substrate in a microwave heating chemical vapor deposition (CVD) system with methane gas at 700 °C. The CNTs grown on Ni–P catalyst showed random orientation and small diameter around 15–30 nm. Field emission test results indicated that the Ni–P catalyzed-CNTs exhibited excellent field emission properties. The turn-on field was about 0.56 V/μm with an emission current density 10 μA/cm2 and the threshold field was 4.4 V/μm with an emission current density 10 mA/cm2. These excellent field emission properties may be attributed to the random orientation and small diameter of CNTs.

Electron Field Emission from Nano-Diamond Films

2001 ◽  
Vol 704 ◽  
Author(s):  
S.G. Wang ◽  
Q. Zhang ◽  
S.F. Yoon ◽  
J. Ahn ◽  
Q. Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Electric Field ◽  
Field Emission ◽  
Current Density ◽  
Diamond Films ◽  
Emission Current Density ◽  
Hydrogen Gas ◽  
Emission Current ◽  
Electron Field Emission ◽  
Electron Field

AbstractIn this paper, the field emission properties of nano-diamond films were investigated by measuring the curves of emission current density (J) versus applied electric field (E). The nano-diamond films were prepared on n-type (100) silicon substrate by microwave plasma enhanced chemical vapor deposition (MPECVD) technique using a gas mixture of nitrogen-methane-hydrogen. Field emission results show that, with increasing hydrogen gas flow ratio of [H2]/[N2+CH4+H2] from 0 to 10 %, diamond grain size increases from 5 to 60 nm, threshold electric field for electron field emission increases from 1.2 to 5.75 V/μm, and emission current density decreases from 820 to 560 μA/cm2, demonstrating that small grain size nano-diamond films are promising as a cathode material for low-field electron emitters.

Influence of Cathode Size on Field Emission Properties of a Single Vertical Carbon Nanotube Material

2016 ◽  
Vol 723 ◽  
pp. 454-458 ◽  
Author(s):  
Li Guo Jing ◽  
He Qiu Zhang ◽  
Yu Qiu ◽  
Bing Yin ◽  
Li Zhong Hu
Keyword(s):  
Carbon Nanotube ◽  
Electric Field ◽  
Field Emission ◽  
Emission Current ◽  
Perfect Conductor ◽  
Current Increase ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Field Emission Current ◽  
Constant Potential

In this work, we study the field emission properties of a single vertical carbon nanotube with cathode radius changing. The carbon nanotube is considered as purely perfect conductor, and the anode and cathode are modeled as discs. The radius of anode is kept as 24m, then the radius of cathode is changed from 24 m to 1 m. The emitter of that CNT consists of a hemispherical cap of 4 nm radius (r) on top of a cylinder height of 2 m (h). The distance from anode to cathode is w=h+20m. The overall surface area of the CNT and cathode are all grounded, and the anode plate has a constant potential value of 100 V. The distribution of potential and electric field, field emission current are obtained by simulating with the help of COMSOL Multiphysics 4.3b electrostatics module. We find that with cathode radius decrease, the electric field strength over the surface of carbon nanotube (CNT) strengthening and field emission current increase.

Large field emission current density from well-aligned carbon nanotube field emitter arrays

2001 ◽  
Vol 1 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Jung Inn Sohn ◽  
Seonghoon Lee ◽  
Yoon-Ho Song ◽  
Sung-Yool Choi ◽  
Kyoung-Ik Cho ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Field Emission ◽  
Current Density ◽  
Emission Current Density ◽  
Emission Current ◽  
Large Field ◽  
Field Emitter ◽  
Field Emitter Arrays ◽  
Field Emission Current ◽  
Field Emission Current Density

Field Emission Characteristics of Orthorhombic Boron Nitride Films

2008 ◽  
Vol 368-372 ◽  
pp. 650-652
Author(s):  
Wei Qing Li ◽  
Yong Nian Zhao
Keyword(s):  
Thin Films ◽  
Boron Nitride ◽  
Electric Field ◽  
Field Emission ◽  
Current Density ◽  
Emission Current Density ◽  
Emission Current ◽  
Vacuum System ◽  
Emission Characteristics ◽  
System A

Orthorhombic boron nitride (o-BN) films with various thickness (150, 220 and 300nm etc.) are prepared on Si(100) substrate by radio frequency plasma enhanced pulsed (Nd:YAG) laser deposition (RF-PEPLD) in Ar-N2 gas system. The films are characterized by Fourier transform infrared spectroscopy and atomic force microscopic. The field emission characteristics of the BN thin films are measured in an ultrahigh vacuum system. A threshold electric field of 8V /6m and the highest emission current density of 157.5mA/cm2 at an electric field of 20V/6m are obtained for the 150nm-thick BN film and a threshold electric field of 18V / 6m and the highest emission current density of 332.9mA/cm2 at an electric field of 52 V/6m are obtained for the 220nm-thick BN film. The results show that the threshold electric field increases with increasing thickness of the films, while the withstand voltage characteristic of the BN films also increases with increasing thickness of the films. The Fowler-Nordheim plots show that electrons emitted from BN to vacuum by tunneling through the potential barrier at the surface of BN thin films.

Suppressed Field Emission Screening Effect and Electric Field Simulation of Carbon Nanotube-Based Triode Field Emitters

2009 ◽  
Vol 154 ◽  
pp. 83-88 ◽  
Author(s):  
Javad Koohsorkhi ◽  
Nima Davoudzadeh ◽  
Shamsoddin Mohajerzadeh ◽  
Ebrahin Asl Soleimani ◽  
Hasan Ghafouri Fard
Keyword(s):  
Electric Field ◽  
Field Emission ◽  
Current Density ◽  
High Current Density ◽  
Emission Current Density ◽  
Emission Current ◽  
Favorable Effect ◽  
Screening Effect ◽  
Field Simulation ◽  
Array Density

In this paper the electric field simulation of carbon nanotubes triode field emission devices is investigated. The geometry of CNTs and their arrangement on the substrate affect the screening effect and filed enhancement factor (β). In an array of nanotubes, for a distance smaller than the CNT length the screening effect is observed. The emission current density is related to the gate aperture and CNT shape. In a triode structure the screening effect occurs in the intertube distances about half of the CNT’s length due to the presence of the gate plate. Furthermore, the presence of the metal-oxide gate has a favorable effect to minimize the screening effect and allows one to increase the density of CNT’s in each array spot and to increase the cluster array density on the substrate, hence to increase the density of emission current and emitter sites where a high current density is required.

Adhesive Enhancement Improved Field Emission Characteristics of Carbon Nanotube Arrays on Energetic Ion Pre-Bombarded Si Substrates

2011 ◽  
Vol 483 ◽  
pp. 589-594 ◽  
Author(s):  
Jian Hua Deng ◽  
Peng Cheng Sun ◽  
Zhao Xia Ping ◽  
Guo An Cheng ◽  
Rui Ting Zheng
Keyword(s):  
Carbon Nanotube ◽  
Field Emission ◽  
Current Density ◽  
Emission Current Density ◽  
Emission Current ◽  
Nanotube Arrays ◽  
Iron Ion ◽  
Si Substrate ◽  
Si Substrates ◽  
Carbon Nanotube Arrays

Field emission (FE) characteristics of well-aligned multiwall carbon nanotube arrays (CNTAs) grown on originally polished and energetic iron ion bombarded Si substrates were investigated. It was found that the FE characteristics have been improved remarkably by the pretreatment of iron ion bombardment, an evident promotion of the highest emission current density from 4.05 mA/cm2to 54.45 mA/cm2was as an expression of this enhancement, this enhancement in characteristics is attributed to the improved adhesion between CNTs and Si substrate for the existence of iron buffer layer. The relationship between adhesive force and emission current density has been introduced, and the calculation reveals that the adhesion has been enhanced by 14.4 times due to the energetic ion pre-bombardment on Si substrate.

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