scholarly journals Screening effects on the field enhancement factor of zigzag graphene nanoribbon arrays: a first-principles study

2018 ◽  
Vol 20 (21) ◽  
pp. 14627-14634 ◽  
Author(s):  
Han Hu ◽  
Tzu-Chien Lin ◽  
Tsan-Chuen Leung ◽  
Wan-Sheng Su
Keyword(s):  
Field Emission ◽  
First Principles ◽  
Enhancement Factor ◽  
Graphene Nanoribbons ◽  
Field Enhancement ◽  
First Principles Calculations ◽  
Screening Effect ◽  
Field Screening ◽  
Field Emission Properties ◽  
Zigzag Graphene Nanoribbons

The field screening effect on the electronic and field-emission properties of zigzag graphene nanoribbons (ZGNRs) has been studied using first-principles calculations.

scholarly journals Strain and screening effects on field emission properties of armchair graphene nanoribbon arrays: a first-principles study

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22625-22634 ◽  
Author(s):  
Han Hu ◽  
Siow Mean Loh ◽  
Tsan-Chuen Leung ◽  
Ming-Chieh Lin
Keyword(s):  
Field Emission ◽  
First Principles ◽  
Graphene Nanoribbons ◽  
Local Density ◽  
First Principles Calculations ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Armchair Graphene Nanoribbons ◽  
Armchair Graphene Nanoribbon ◽  
Armchair Graphene

The field screening effect on the field-emission properties of armchair graphene nanoribbons (AGNRs) under strain has been studied using first-principles calculations with local density approximation (LDA).

scholarly journals Microconical Structure Formation and Field Emission From Atomically Heterogeneous Surfaces Created by Microwave Plasma–Based Low-Energy Ion Beams

2021 ◽  
Vol 9 ◽  
Author(s):  
Jayashree Majumdar ◽  
Sudeep Bhattacharjee
Keyword(s):  
Work Function ◽  
Field Emission ◽  
Enhancement Factor ◽  
Field Enhancement ◽  
Ion Beams ◽  
Emission Current ◽  
Force Microscopy ◽  
Field Emission Properties ◽  
Argon Ion ◽  
Local Work

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.

Field Emission Site Densities of Nanostructured Carbon

2001 ◽  
Vol 675 ◽  
Author(s):  
J B Cui ◽  
J Robertson ◽  
W I Milne
Keyword(s):  
Field Emission ◽  
Applied Field ◽  
Enhancement Factor ◽  
Field Enhancement ◽  
Carbon Films ◽  
Vacuum Arc ◽  
Nanostructured Carbon ◽  
Field Emission Properties ◽  
Site Density ◽  
Enhancement Factors

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.

Electron Transport in Zigzag Graphene Nanoribbons with a Tetra-Vacancy Complex: A Perfect Spin Filter

2014 ◽  
Vol 937 ◽  
pp. 207-213 ◽  
Author(s):  
Wei Lu ◽  
San Huang Ke
Keyword(s):  
Electronic Structure ◽  
Electron Transport ◽  
First Principles ◽  
Graphene Nanoribbons ◽  
Wide Energy Range ◽  
First Principles Calculations ◽  
Spin Filter ◽  
Spin Polarized ◽  
Wide Energy ◽  
Zigzag Graphene Nanoribbons

A novel doping scheme for graphene was recently realized experimentally by creating different vacancy complexes doped with a transition metal (TM) atom [nanoLett. 12, 141 (2012)]. This provides a new reliable way to modifying the electronic structure and transport property of graphene. Here, we show, by performing first-principles calculations, that the defect complex of TM@V4(a TM atom doped tetra-vacancy) in zigzag graphene nanoribbons (ZGNRs) can lead to a 100% spin-polarized electron transport in a wide energy range around the Fermi energy. Analyses show that this is due to the particular atomic structure of the TM@V4complex regardless of the species of the TM atom.

Field Emission from Nanocrystalline Diamond/Carbon Nanowall Composite Films Deposited on Scratched Substrates

2012 ◽  
Vol 1395 ◽  
Author(s):  
C.Y. Cheng ◽  
M. Nakashima ◽  
K. Teii
Keyword(s):  
Field Emission ◽  
Enhancement Factor ◽  
Composite Films ◽  
Diamond Films ◽  
Field Enhancement ◽  
Nanocrystalline Diamond ◽  
Field Emission Properties ◽  
Turn On ◽  
Carbon Nanowalls ◽  
Wall Spacing

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.

Field emission properties of spinel ZnCo2O4 microflowers

RSC Advances ◽  
2015 ◽  
Vol 5 (7) ◽  
pp. 5372-5378 ◽  
Author(s):  
Satyajit Ratha ◽  
Ruchita T. Khare ◽  
Mahendra A. More ◽  
Ranjit Thapa ◽  
Dattatray J. Late ◽  
...  
Keyword(s):  
Field Emission ◽  
Enhancement Factor ◽  
Field Enhancement ◽  
Field Enhancement Factor ◽  
Emission Performance ◽  
Emission Properties ◽  
Field Emission Properties ◽  
Field Emission Performance ◽  
Facile Route

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.

scholarly journals Small-Sized Flat-Tip CNT Emitters for Miniaturized X-Ray Tubes

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Hyun Jin Kim ◽  
Jun Mok Ha ◽  
Sung Hwan Heo ◽  
Sung Oh Cho
Keyword(s):  
Silver Nanoparticles ◽  
Electric Field ◽  
Field Emission ◽  
Enhancement Factor ◽  
Flat Surface ◽  
Field Enhancement ◽  
X Ray ◽  
Field Emission Properties ◽  
Inner Diameter ◽  
Metal Tip

Small tip-type CNT emitters with the diameter of 0.8 mm were fabricated for miniaturized X-ray tubes. The CNT emitters were prepared by dropping CNTs and silver nanoparticles on a flat surface of a W metal tip followed by annealing at 800°C for 2 h under vacuum. The CNT emitters exhibit good field emission properties with the threshold electric field of 1.15 V/μm and the field enhancement factor of 12,050. CNTs were well attached to a flat W tip surface without coating on the side plane of the tip, and thus beam divergence could be minimized. Consequently, a miniaturized X-ray tube with the inner diameter of 5 mm was successfully demonstrated using the tip-type CNT emitter.

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