Fibrous structures on diamond and carbon surfaces formed by hydrogen plasma under direct-current bias and field electron-emission properties

2003 ◽  
Vol 18 (2) ◽  
pp. 305-326 ◽  
Author(s):  
Koji Kobashi ◽  
Takeshi Tachibana ◽  
Yoshihiro Yokota ◽  
Nobuyuki Kawakami ◽  
Kazushi Hayashi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Direct Current ◽  
Electron Emission ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Polycrystalline Diamond ◽  
Metal Catalyst ◽  
Direct Current Bias ◽  
Conical Structures

Polycrystalline diamond films, single crystal bulk diamonds, and diamond powder were treated in microwave plasma of hydrogen at 1.6 torr under a negative direct-current bias of −150 to −300 V without metal catalyst. It was found that fibrous structures, uniformly elongated along the direction normal to the specimen surface, were formed on the diamond surfaces. Similar experiments for glasslike carbon resulted in conical structures with frizzy fibers at the tops. Transmission electron microscopy measurements indicated that the fibers formed on diamond consisted of randomly oriented diamond nanocrystals with diameters of less than 10 nm, while the conical structures formed on glasslike carbon consisted of graphite nanocrystals. Field emission measurements of the fibrous specimens exhibited better emission efficiency than untreated ones. The field emission electron microscopy of the fibrous glasslike carbon showed a presence of discrete electron emission sites at a density of approximately 10,000 sites/cm2.

Study of Field Emission Behavior of Carbon Nanotubes with Different Sources

2002 ◽  
Vol 728 ◽  
Author(s):  
Mark Ching-Cheng Lin ◽  
M.S. Lai ◽  
H. J. Lai ◽  
M. H. Yang ◽  
B.Y. Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Field Emission ◽  
Arc Discharge ◽  
Metal Catalyst ◽  
Microstructural Investigation ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Different Sources

AbstractThe field emission properties of carbon nanotubes (CNTs) from various sources are investigated for the application of field emission displays. Comparisons are made between graphite with Ni metal as catalyst and polycyclic aromatic hydrocarbon as precursor by the arc discharge method. Cathode deposits are examined using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) to determine microstructure. Carbon structure is studied using Raman spectroscopy. Electron field emission characteristics are measured with the diode method at 10-6 torr pressure. In this study, SEM micrographs of cathode deposits show dense random fiber-like carbon nanotubes. The HRTEM images clearly exhibit characteristic features of multiwalled carbon nanotubes. Microstructural investigation provides evidence that both the metal catalyst and the precursor can be used to synthesize carbon nanotubes. The Raman spectrum shows a stronger peak at about 1580 cm-1 indicating formation of a well-graphitized carbon nanotube. The degree of carbon nanotube graphitization is high and is in good agreement with the HRTEM result. From field emission measurements, the lowest onset field is about 1.0 V/μm and can be attributed to highly sharp tips and the high density of carbon nanotubes. Based on microstructure characterization and field emission measurements, the influence on field emission properties including turn on voltage and threshold voltage of carbon nanotubes synthesized from different sources is discussed.

scholarly journals The Field Emission Properties of Graphene Aggregates Films Deposited on Fe-Cr-Ni alloy Substrates

2010 ◽  
Vol 2010 ◽  
pp. 1-4 ◽  
Author(s):  
Zhanling Lu ◽  
Wanjie Wang ◽  
Xiaotian Ma ◽  
Ning Yao ◽  
Lan Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Plasma Chemical ◽  
Raman Scattering Spectroscopy ◽  
Emission Properties ◽  
Plasma Chemical Vapor Deposition ◽  
Field Emission Properties ◽  
Ni Alloy

The graphene aggregates films were fabricated directly on Fe-Cr-Ni alloy substrates by microwave plasma chemical vapor deposition system (MPCVD). The source gas was a mixture of and with flow rates of 100 sccm and 12 sccm, respectively. The micro- and nanostructures of the samples were characterized by Raman scattering spectroscopy, field emission scanning electron microscopy (SEM), and transparent electron microscopy (TEM). The field emission properties of the films were measured using a diode structure in a vacuum chamber. The turn-on field was about 1.0 V/m. The current density of 2.1 mA/ at electric field of 2.4 V/m was obtained.

Field Electron Emission from Carbon Nanotube Films on Diamond Films

2005 ◽  
Vol 475-479 ◽  
pp. 3587-3590
Author(s):  
K.J. Liao ◽  
W.L. Wang ◽  
Y.T. Wang ◽  
J.W. Lu ◽  
X.L. Sun
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Field Emission ◽  
Electron Emission ◽  
Diamond Films ◽  
Chemical Vapour ◽  
Polycrystalline Diamond ◽  
Field Electron Emission ◽  
Field Electron ◽  
Nanotube Films

The field electron emission from carbon nanotube films on polycrystalline diamond films was investigated. The carbon nanotubes and diamond films on Si substrates were prepared by a conventional hot filament chemical vapour deposition. The films obtained were characterized by scanning electron microscopy and Raman spectroscopy. The field emission properties of the samples were measured in an ion-pumped vacuum chamber at a pressure of 10-6 Pa.. The experimental results showed that the field emission behaviours of carbon nanotubes/diomond films structure have greatly been improved as compared with carbon nanotubes and diamond films, respectively. A turn-on field of 1.0 V/µm and a maximum current of 500 µA at 1.5 V/µm were observed, which were lower than those of carbon nanotubes and polycrystalline diamond films, respectively. This improvement was attributed to the tip shape of sample surface, which provided an additional local increase in electric field at the tube ends.

Preparation and Field Emission Characteristics of CNx Nanotubes Thin Film

2005 ◽  
Vol 475-479 ◽  
pp. 3595-3598
Author(s):  
Lan Zhang ◽  
Hui Zhong Ma ◽  
Xue Xiang Li ◽  
Ning Yao ◽  
Bing Lin Zhang
Keyword(s):  
Thin Films ◽  
Field Emission ◽  
Electron Emission ◽  
Photoelectron Spectroscopy ◽  
Microwave Plasma ◽  
Field Electron Emission ◽  
Emission Characteristics ◽  
Flow Ratio ◽  
X Ray ◽  
Field Electron

Carbon nitride nanotubes (CN-NT) thin films were prepared on Ni-Cr coated glass substrate by microwave plasma enhanced chemical vapor deposition at a relatively low temperature of 600～650 °C. The morphology of the films were observed by scanning electron microscopy. The microstructure of the film were analyzed by x-ray photoelectron spectroscopy, x-ray diffraction, and Raman spectroscopy. The characteristics of field emission of CN-NT thin films were measured. Experimental results indicate that the film structure and properties of the field electron emission are related to flow ratio of N2 to CH4. When the flow ratio of N2 to CH4 was 3.3, the obtained film had a better field electron emission characteristics. The turn-on field of the film was 3.7 V/µm . The current density was 413.3 µA/cm2 at an electric field of 8 V/µm.

Electron Emission Properties of Si Field Emitter Arrays Coated With Nanocrystalline Diamond From Fullerene Precursors

1997 ◽  
Vol 498 ◽  
Author(s):  
T. G. McCauley ◽  
T. D. Corrigan ◽  
A. R. Krauss ◽  
O. Auciello ◽  
D. Zhou ◽  
...  
Keyword(s):  
Field Emission ◽  
Electron Emission ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Threshold Field ◽  
Field Emitter ◽  
Effective Work ◽  
Field Emitter Arrays ◽  
Electron Field

ABSTRACTIn this paper, we report on a substantial lowering of the threshold field for electron field emission from Si field emitter arrays (FEA), which have been coated with a thin layer of nanocrystalline diamond by microwave plasma-assisted chemical vapor deposition (MPCVD) from fullerene (C60) and methane (CH4) precursors. The field emission characteristics were investigated and the emission sites imaged using photoelectron emission microscopy (PEEM). Electron emission from these Si FEAs coated with nanocrystalline diamond was observed at threshold fields as low as 3 V/μm, with effective work functions as low as 0.59 eV.

Electrical Properties of Hydrogen Terminated P-Type Diamond Film

2010 ◽  
Vol 663-665 ◽  
pp. 625-628
Author(s):  
Fu Yuan Xia ◽  
Lin Jun Wang ◽  
Jian Huang ◽  
Ke Tang ◽  
Ji Jun Zhang ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
P Type ◽  
Effect Method

Undoped high quality polycrystalline diamond films were grown by the microwave plasma chemical vapor deposition (MPCVD) method. The effects of hydrogen plasma treatment and vacuum annealing process on the p-type behavior of diamond films were investigated by the Hall effect method. The sheet carrier concentration increased and the sheet resistivity decreased with the treating time of hydrogen plasma and a stable value was achieved finally. After annealing the samples in vacuum at temperature above 600 °C, the sheet carrier concentration dropped dramatically. The origin of this hydrogen terminated p-type conductive layers is also discussed.

FIELD EMISSION FROM CARBON NANOTUBES PRODUCED USING MICROWAVE PLASMA ASSISTED CVD

2000 ◽  
Vol 14 (02n03) ◽  
pp. 289-294 ◽  
Author(s):  
QING ZHANG ◽  
S. F. YOON ◽  
J. AHN ◽  
BO GAN ◽  
RUSLI ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Field Emission ◽  
Electric Fields ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Growth Direction ◽  
Electron Field Emission ◽  
Iron Oxide Particles ◽  
High Emission ◽  
Electron Field

Electron field emission from carbon nanotubes prepared using microwave plasma assisted CVD has been investigated. The nanotubes, ranging from 50 to 120 nm in diameter and a few tens of microns in length, were formed under methane and hydrogen plasma at 720°C with the aid of iron-oxide particles. The morphology and growth direction of the nanotubes are found to be strongly influenced by the flow ratio of methane to hydrogen. However, the electron field emission from these massive mantubes show similar characteristics, i.e., high emission current at low electric fields.

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