scholarly journals Field Emission from Carbon Films Deposited by Controlled-Low-Energy Beams and CVD Sources

1999 ◽  
Vol 585 ◽  
Author(s):  
Douglas H. Lowndes ◽  
Vladimir I. Merkulov ◽  
L. R. Baylor ◽  
G. E. Jellison ◽  
D. B. Poker ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Morphology ◽  
Field Emission ◽  
Metal Ion ◽  
Ion Beam ◽  
Pyrolytic Graphite ◽  
Carbon Film ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Damage Site

AbstractThe principal interests in this work are energetic-beam control of carbon-film properties and the roles of doping and surface morphology in field emission. Carbon films with variable sp3-bonding fraction were deposited on n-type Si substrates by ArF (193 nm) pulsed-laser ablation (PLA) of a pyrolytic graphite target, and by direct metal ion beam deposition (DMIBD) using a primary Cs+ beam to generate the secondary C- deposition beam. The PLA films are undoped while the DMIBD films are doped with Cs. The kinetic energy (KE) of the incident C atoms/ions was controlled and varied over the range from ∼25 eV to ∼175 eV. Earlier studies have shown that C films' sp3-bonding fraction and diamond-like properties can be maximized by using KE values near 90 eV. The films' surface morphology, sp3–bonding fraction, and Cs-content were determined as a function of KE using atomic force microscopy, TEM/EELS, Rutherford backscattering and nuclear reaction measurements, respectively. Field emission (FE) from these very smooth undoped and Cs-containing films is compared with the FE from two types of deliberately nanostructured carbon films, namely hot-filament chemical vapor deposition (HF-CVD) carbon and carbon nanotubes grown by plasma-enhanced CVD. Electron field emission (FE) characteristics were measured using ∼25-μm, ∼5-μm and ∼1-μm diameter probes that were scanned with ∼75 nm resolution in the x-, y-, and z-directions in a vacuum chamber (∼5 × 10-7 torr base pressure) equipped with a video camera for viewing. The hydrogen-free and very smooth a-D or a-C films (with high or low sp3 content, and with or without ∼1% Cs doping) produced by PLD and DMIBD are not good field emitters. Conditioning accompanied by arcing was required to obtain emission, so that their subsequent FE is characteristic of the arc-produced damage site. However, deliberate surface texturing can eliminate the need for conditioning, apparently by geometrical enhancement of the local electric field. But the most promising approach for producing macroscopically flat FE cathodes is to use materials that are highly nanostructured, either by the deposition process (e.g. HF-CVD carbon) or intrinsically (e.g. carbon nanotubes). HF-CVD films were found to combine a number of desirable properties for FE displays and vacuum microelectronics, including the absence of conditioning, low turn-on fields, high emission site density, and apparent stability and durability during limited long-term testing. Preliminary FE measurements revealed that vertically aligned carbon nanotubes are equally promising.

Electron Field Emission from Graphitic Nanoflakes Grown Over Vertically Aligned Carbon Nanotubes

2008 ◽  
Vol 8 (8) ◽  
pp. 4309-4313 ◽  
Author(s):  
S. Chhoker ◽  
S. K. Arora ◽  
P. Srivastava ◽  
V. D. Vankar
Keyword(s):  
Carbon Nanotubes ◽  
Surface Area ◽  
Field Emission ◽  
Deposition Time ◽  
Microwave Plasma ◽  
High Surface ◽  
Carbon Film ◽  
High Surface Area ◽  
Carbon Films ◽  
Single Step

Single step growth of self-assembled graphitic nanoflakes (GNF) over carbon nanotubes (CNT) on iron coated silicon(100) substrates is reported. These nanostructures were grown by varying the deposition time in a microwave plasma enhanced chemical vapor deposition reactor using acetylene, hydrogen and argon as reactant gases. Scanning electron microscope (SEM) studies of the deposited carbon films revealed that with increase in deposition time from 3 minutes to 6 minutes, the surface topography of the films transformed from one dimensional cylindrical nanostructure to flat-shaped two-dimensional nanoflakes. Carbon film deposited for 5 minutes showed improved surface coverage as compared to films deposited for 6 minutes i.e., surface area of the CNT film covered with nanoflakes increased as compared to carbon film deposited for higher durations. Field emission studies of films deposited at 5 minutes and 6 minutes showed increase in turn-on field, required for electron emission, from 2.7 V/μm to 2.9 V/μm respectively. However, such a combination of one dimension carbon and two dimension carbon may prove useful in applications where high surface area films are required.

scholarly journals Direct Deposition of Bamboo-Like Carbon Nanotubes on Copper Substrates by Sulfur-Assisted HFCVD

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Sri Lakshmi Katar ◽  
Adolfo González-Berríos ◽  
Joel De Jesus ◽  
Brad Weiner ◽  
Gerardo Morell
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Substrate Temperature ◽  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Growth Time ◽  
Electron Field Emission ◽  
Electron Field

Films of bamboo-like carbon nanotubes (BCNTs) were grown directly on copper substrates by sulfur-assisted hot filament chemical vapor deposition (HFCVD). The effects of substrate temperature and growth time over the BCNT structure were investigated. The films were characterized by scanning electron microscopy (SEM), Raman spectroscopy (RS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electron field emission (EFE) studies. SEM and Raman characterization indicate a transition from the growth of microcrystalline diamond to the growth of a dense entangled network of carbon nanotubes or fibers as the substrate temperature is increased from 400 to900°Cthat is accounted for by the base growth model. TEM images show that the nanotubes have regular arrays of nanocavities. These BCNTs show good electron field emission properties as other carbon films.

Carbon Film Deposition On Silicon Using Low Energy Ion Beams

1991 ◽  
Vol 223 ◽  
Author(s):  
Qin Fuguang ◽  
Yao Zhenyu ◽  
Ren Zhizhang ◽  
S.-T. Lee ◽  
I. Bello ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ion Beam ◽  
Carbon Film ◽  
Carbon Films ◽  
Film Deposition ◽  
Ion Energy ◽  
Transmission Electron ◽  
Higher Temperature ◽  
Post Implantation ◽  
Beam Deposition

ABSTRACTDirect ion beam deposition of carbon films on silicon in the ion energy range of 15–500eV and temperature range of 25–800°C has been studied using mass selected C+ ions under ultrahigh vacuum. The films were characterized with X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy and diffraction analysis. Films deposited at room temperature consist mainly of amorphous carbon. Deposition at a higher temperature, or post-implantation annealing leads to formation of microcrystalline graphite. A deposition temperature above 800°C favors the formation of microcrystalline graphite with a preferred orientation in the (0001) direction. No evidence of diamond formation was observed in these films.

Surface morphology of ion-beam deposited carbon films under high temperature

2002 ◽  
Vol 20 (6) ◽  
pp. 2072
Author(s):  
Meiyong Liao ◽  
Chunlin Chai ◽  
Shaoyan Yang ◽  
Zhikai Liu ◽  
Fuguang Qin ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Morphology ◽  
Ion Beam ◽  
Carbon Films

Field emission properties of nitrogen-doped diamond-like carbon films deposited by direct metal ion beam deposition

2001 ◽  
Vol 697 ◽  
Author(s):  
Kie Moon Song ◽  
Namwoong Paik ◽  
Steven Kim ◽  
Daeil Kim ◽  
Seongjin Kim ◽  
...  
Keyword(s):  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Nitrogen Doping ◽  
Ion Beam ◽  
Diamond Like Carbon ◽  
Emission Data ◽  
Nitrogen Doped ◽  
Ion Beam Deposition ◽  
Beam Deposition

AbstractNitrogen-doped diamond-like carbon (DLC) films were deposited on a silicon substrate by direct metal ion beam deposition (DMIBD). Partial pressures of nitrogen gas were changed to get different compositions of nitrogen in the DLC films. The composition and surface morphology of the films were examined using X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). Effect of nitrogen doping on field emission property was studied. The field emission data indicated that the nitrogen doping lowered the turn-on field and increase the current density. It was believed that doping of nitrogen into the DLC film plays an important role in enhancement of the field emission. This enhancement of field emission could be explained by the improvement of electron transport through nitrogen-dope DLC layer.

Growth of diamond and diamond-like films using a low energy ion beam

1998 ◽  
Vol 13 (8) ◽  
pp. 2315-2320 ◽  
Author(s):  
Y. P. Guo ◽  
K. L. Lam ◽  
K. M. Lui ◽  
R. W. M. Kwok ◽  
K. C. Hui
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Low Energy ◽  
Hydrogen Passivation ◽  
Heteroepitaxial Growth ◽  
Ion Beam Deposition ◽  
Additional Control ◽  
Strain Release ◽  
Beam Deposition

Ion beam deposition provides an additional control of ion beam energy over the chemical vapor deposition methods. We have used a low energy ion beam of hydrogen and carbon to deposit carbon films on Si(100) wafers. We found that graphitic films, amorphous carbon films, and oriented diamond microcrystallites could be obtained separatedly at different ion beam energies. The mechanism of the formation of the oriented diamond microcrystallites was suggested to include three components: strain release after ion bombardment, hydrogen passivation of sp3 carbon, and hydrogen etching. Such a process can be extended to the heteroepitaxial growth of diamond films.

Large field emission from carbon nanotubes grown on patterned catalyst thin film by thermal chemical vapor deposition

2002 ◽  
Vol 323 (1-4) ◽  
pp. 171-173 ◽  
Author(s):  
Takashi Ikuno ◽  
Tetsuro Yamamoto ◽  
Motoki Kamizono ◽  
Syunji Takahashi ◽  
Hiroshi Furuta ◽  
...  
Keyword(s):  
Thin Film ◽  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Field Emission ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Large Field ◽  
Thermal Chemical Vapor Deposition
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