Field Emission Site Densities of Nanostructured Carbon

2001 ◽  
Vol 675 ◽  
Author(s):  
J B Cui ◽  
J Robertson ◽  
W I Milne

ABSTRACTThe field emission properties of nanostructured carbon films deposited by cathodic vacuum arc in a He atmosphere have been studied by measuring the emission currents and the emission site density. The films have an onset field of ∼3 V/μm. The emission site density is viewed on a phosphor anode and it increases rapidly with applied field. It is assumed that the emission occurs from surface regions with a range of field enhancement factors but with a constant work function. The field enhancement factor is found to have an exponential distribution.

2002 ◽  
Vol 92 (9) ◽  
pp. 5482-5489 ◽  
Author(s):  
C. Ducati ◽  
E. Barborini ◽  
P. Piseri ◽  
P. Milani ◽  
J. Robertson

2002 ◽  
Vol 35 (4) ◽  
pp. 357-362 ◽  
Author(s):  
A N Obraztsov ◽  
A P Volkov ◽  
K S Nagovitsyn ◽  
K Nishimura ◽  
K Morisawa ◽  
...  

1997 ◽  
Vol 498 ◽  
Author(s):  
A. P. Burden ◽  
R. Forrest ◽  
S.R.P. Silva ◽  
B. J. Sealy ◽  
G.A.J. Amaratunga

ABSTRACTThe field emission properties of a variety of nitrogen-containing hydrogenated amorphous carbon films have been characterised as a function of film thickness and substrate type. Identified trends have been discussed in terms of the optical band-gap and refractive index of the films, and the surface roughness of the substrates. In addition, carbon-based materials have been considered as inexpensive film-compatible substrates, and an in-situ oxygen plasma pre-treatment has been investigated as a means of changing the field enhancement factor of the system. We have achieved field emission with threshold voltages as low as 8 V μm−1, and we present data that supports the view that the electron emission from amorphous carbon is dependent on the nature of the back contact, and possibly the ease at which the film can be fully depleted, i.e. film thickness.


2007 ◽  
Vol 7 (2) ◽  
pp. 570-574
Author(s):  
Yang Doo Lee ◽  
V. D. Blank ◽  
D. V. Batov ◽  
S. G. Buga ◽  
Yun-Hi Lee ◽  
...  

Carbon–nitrogen (CN) nanofibers were synthesized in argon–nitrogen gas mixture at 75 MPa by high isostatic pressure (HIP) apparatus using a graphite resistive heater. The CN nanofibers were grown in random with the diameter of about 200 nm and the length over 5 μm. The structures obtained can be divided bamboo-like, spring-like, and bead necklace-like CN nanofibers. The nitrogen content of up to 8.4% was found in CN nanofibers by EELS analysis. Field emission results showed that the density of field emitters and the field enhancement factors changed by surface treatments and that CN nanofibers contained glass frit. The screen-printed CN nanofiber had a turn-on field of 2 V/μm.


2021 ◽  
Vol 9 ◽  
Author(s):  
Jayashree Majumdar ◽  
Sudeep Bhattacharjee

We report the formation of self-organized microconical arrays on copper surface when exposed to high flux (5.4 × 1015 cm−2 s−1) of 2 keV argon ion beams at normal incidence. The created microconical arrays are explored for field emission properties. The surface morphologies are investigated by scanning electron microscopy and atomic force microscopy. The local work function variation is analyzed by Kelvin probe force microscopy, and the argon content in the irradiated layer is measured with X-ray Photoelectron Spectroscopy. The average aspect ratio (base width/height) of microstructures for individual irradiated samples is found to increase from 0.7 to 1.5 with a decrease in ion fluence. The ion concentration is highest (3.89 %) for a fluence of 4.7 × 1018 cm−2, which asserts the formation of atomically heterogeneous surface due to subsurface ion implantation. An enhancement in the field emission properties of the argon ion–treated copper substrates at a fluence of 4.7 × 1018 cm−2 with a low turn-on voltage of 2.33 kV and with electron emission current 0.5 nA has been observed. From the Fowler–Nordheim equations, the field enhancement factor is calculated to be 5,561 for pristine copper, which gets enhanced by a factor of 2–8 times for irradiated substrates. A parametric model is considered, by taking into account the modified local work function caused due to structural undulations of the microstructures and presence of implanted argon ions, for explaining the experimental results on the field enhancement factor and emission current.


2012 ◽  
Vol 1395 ◽  
Author(s):  
C.Y. Cheng ◽  
M. Nakashima ◽  
K. Teii

ABSTRACTWe report the deposition and field emission properties of nanostructured composites consisting of carbon nanowalls (CNWs) and nanocrystalline diamond films by introducing two kinds of substrate scratching pretreatment, i.e., undulation and ultrasonic vibration. With increasing duration of scratching pretreatment, the morphology of the deposits changes from simple CNWs to a film/CNW composite and lastly to CNWs on a film, and then the space between the walls is increased. The emission turn-on field is reduced from 2.1 V/μm for simple CNWs to around 1.2 V/μm for the composite films, accompanied by an increase in field enhancement factor. The results indicate that electric field screening between the walls is successfully suppressed by widening of the wall spacing.


RSC Advances ◽  
2015 ◽  
Vol 5 (7) ◽  
pp. 5372-5378 ◽  
Author(s):  
Satyajit Ratha ◽  
Ruchita T. Khare ◽  
Mahendra A. More ◽  
Ranjit Thapa ◽  
Dattatray J. Late ◽  
...  

Spinel ZnCo2O4 microflowers were synthesized by a facile route and their field emission properties were studied in detail. They showed intriguing Field emission performance in terms of good field-enhancement factor and stability.


1997 ◽  
Vol 498 ◽  
Author(s):  
B. F. Coll ◽  
J. E. Jaskie ◽  
J. L. Markham ◽  
E. P. Menu ◽  
A. A. Talin ◽  
...  

ABSTRACTThe fabrication of an efficient cold cathode emitter from carbon is based on a combination of material properties, which must be carefully tailored during deposition. We present the electron emission characteristics of several carbon films deposited by cathodic arc evaporation, and their correlation with the chemical composition, microtexture and microstructure of the films. The emission threshold field voltage, emission site density, uniformity and stability of both tetrahedral amorphous carbon, nitrogen doped carbon and nanoclustered carbon films will be reviewed. We will also address issues related to the deposition method, such as substrate temperature, defect density and scalability, in connection with requirements for the fabrication of field emission displays.


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