scholarly journals Characterisation of thermionic emission current with a laser-heated system

2019 ◽  
Vol 90 (4) ◽  
pp. 045110 ◽  
Author(s):  
Hugo Dominguez-Andrade ◽  
Alex Croot ◽  
Gary Wan ◽  
James A. Smith ◽  
Neil A. Fox
Keyword(s):  
Thermionic Emission ◽  
Emission Current ◽  
Laser Heated

A New Thermionic Cathode Based on Carbon Nanotubes with a Thin Layer of Low Work Function Barium Strontium Oxide Surface Coating

2008 ◽  
Vol 1142 ◽  
Author(s):  
Feng Jin ◽  
Yan Liu ◽  
Scott A Little ◽  
Chris M Day
Keyword(s):  
Work Function ◽  
Current Density ◽  
Enhancement Factor ◽  
Thermionic Emission ◽  
Field Enhancement ◽  
Oxide Coating ◽  
Emission Current Density ◽  
Emission Current ◽  
Strontium Oxide ◽  
Barium Strontium

ABSTRACTWe have created a thermionic cathode structure that consists of a thin tungsten ribbon; carbon nanotubes (CNTs) on the ribbon surface; and a thin layer of low work function barium strontium oxide coating on the CNTs. This oxide coated CNT cathode was designed to combine the benefits from the high field enhancement factor from CNTs and the low work function from the emissive oxide coating. The field emission and thermionic emission properties of the cathode have been characterized. A field enhancement factor of 266 and a work function of 1.9 eV were obtained. At 1221 K, a thermionic emission current density of 1.22A/cm2 in an electric field of 1.1 V/μm was obtained, which is four orders of magnitude greater than the emission current density from the uncoated CNT cathode at the same temperature. The high emission current density at such a modest temperature is among the best ever reported for an oxide cathode.

scholarly journals Mathematical models for thermionic emission current density of graphene emitter

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olukunle C. Olawole ◽  
Dilip K. De ◽  
Sunday O. Oyedepo ◽  
Fabian I. Ezema
Keyword(s):  
Mathematical Models ◽  
Current Density ◽  
Coefficient Of Thermal Expansion ◽  
Thermionic Emission ◽  
Emission Current Density ◽  
Least Square ◽  
Emission Current ◽  
Two Dimensional Materials ◽  
Current Emission ◽  
Thermionic Energy

AbstractIn this study, five mathematical models were fitted in the absence of space charge with experimental data to find a more appropriate model and predict the emission current density of the graphene-based thermionic energy converter accurately. Modified Richardson Dushman model (MRDE) shows that TEC's electron emission depends on temperature, Fermi energy, work function, and coefficient of thermal expansion. Lowest Least square value of $$S=\sum {\left({J}_{th}-{J}_{exp}\right)}^{2}=0.0002 \,\text{A}^{2}/\text{m}^{4}$$ S = ∑ J th - J exp 2 = 0.0002 A 2 / m 4 makes MRDE most suitable in modelling the emission current density of the graphene-based TEC over the other four tested models. The developed MRDE can be adopted in predicting the current emission density of two-dimensional materials and also future graphene-based TEC response.

Zero bias emission current in laser heated emissive probe and proper choice of probe-tip material

2019 ◽  
Vol 26 (5) ◽  
pp. 053501
Author(s):  
P. Pandit ◽  
A. Sarma ◽  
J. Ghosh ◽  
Vara Prasad Kella ◽  
N. Ramaiya ◽  
...  
Keyword(s):  
Emission Current ◽  
Proper Choice ◽  
Zero Bias ◽  
Laser Heated ◽  
Emissive Probe

Forward Thermionic Emission Current of an Inhomogeneous Contact to Cadmium Chalcogenide

1987 ◽  
Vol 102 (2) ◽  
pp. 719-724 ◽  
Author(s):  
V. B. Bikbaev ◽  
S. Č. Karpinskas ◽  
V. E. Stoškus ◽  
J. J. Vaitkus
Keyword(s):  
Thermionic Emission ◽  
Emission Current ◽  
Cadmium Chalcogenide

Real-time monitoring of diamond nucleation and growth using field-enhanced thermionic emission current

2007 ◽  
Vol 254 (5) ◽  
pp. 1423-1426 ◽  
Author(s):  
Y.X. Han ◽  
M. Zhao ◽  
J. Sun ◽  
H. Ling ◽  
T. Gebre ◽  
...  
Keyword(s):  
Real Time ◽  
Thermionic Emission ◽  
Nucleation And Growth ◽  
Emission Current ◽  
Real Time Monitoring ◽  
Diamond Nucleation

Thermionic electron emission in the 1D edge-to-edge limit

2021 ◽  
Author(s):  
Tongyao Zhang ◽  
Hanwen Wang ◽  
Xiuxin Xia ◽  
Chengbing Qin ◽  
Xiaoxi Li
Keyword(s):  
Integrated Circuits ◽  
Thermionic Emission ◽  
Emission Current ◽  
Great Promise ◽  
Great Success ◽  
Vacuum Tube ◽  
Maximum Emission ◽  
Physical Limit ◽  
On Chip ◽  
Vacuum Gaps

Abstract Thermionic emission is a tunneling phenomenon, which depicts that electrons on the surface of a conductor can be pulled out into the vacuum when they are subjected to high electrical tensions while being heated hot enough to overtake their work functions. This principle has led to the great success of the so-called vacuum tubes in the early 20th century. To date, major challenges still remain in the miniaturization of a vacuum channel transistor for on-chip integration in modern solid-state integrated circuits. Here, by introducing nano-sized vacuum gaps (~200 nm) in a van der Waals heterostructure, we successfully fabricated a one-dimensional (1D) edge-to-edge thermionic emission vacuum tube using graphene as the filament. With the increasing collector voltage, the emitted current exhibited a typical rectifying behavior, with the maximum emission current reaching 200 pA and an On-Off ratio of 103. Besides, it is found that the maximum emission current was proportional to the number of the layers of graphene. Our results expand the studies of the nano-sized vacuum tube to an unexplored physical limit of 1D edge-to-edge emission, and hold great promise for future nano-electronic systems based on it.

scholarly journals Квантовая теория эмиссии электронов из структуры "металл-диэлектрик" в сильных электрических полях

2020 ◽  
Vol 90 (6) ◽  
pp. 1035
Author(s):  
С.И. Берил ◽  
С.А. Баренгольц ◽  
Ю.А. Баренгольц ◽  
А.С. Старчук
Keyword(s):  
Work Function ◽  
Field Emission ◽  
Electric Fields ◽  
Electron Emission ◽  
Thermionic Emission ◽  
Emission Current ◽  
Electronic Work Function ◽  
Quantum Image ◽  
Field Emission Current ◽  
Increasing Temperature

A generalized formula is derived for the electron emission current in relation to the temperature, the electric field, and the electronic work function for a “metal–dielectric” system. The formula takes into account the quantum nature of the image forces. In deriving it, the Fermi–Dirac distribution and the quantum image potential obtained in terms of the electron–polaron theory are used. In the limit of the classical potential of image forces, the well-known Richardson–Schottky and Fowler–Nordheim formulas are obtained for thermionic emission and field emission, respectively. It is shown that at high temperatures and electric fields E ≥ 10 MV/cm, the polaron contribution to the electron emission current increases with increasing field and decreases with increasing temperature. The decrease in current is related to an increase in effective electronic work function due to the electron-polaron effect. Extrapolation formulas convenient to obtain theoretical estimates are derived for the thermionic and the field emission current.

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