A low-voltage field-emission column with a Schottky emitter

1984 ◽  
Vol 42 ◽  
pp. 454-457
Author(s):  
D.W. Tuggle ◽  
S.G. Watson
Keyword(s):  
Field Emission ◽  
Low Voltage ◽  
High Current Density ◽  
High Vacuum ◽  
Energy Spread ◽  
Electron Gun ◽  
Emission Current ◽  
High Current ◽  
Field Mode ◽  
Over The Top

The advantages of a room-temperature field emission (FE) cathode for forming a sub-micrometer high current, low voltage electron probe, namely small energy spread, high brightness and a small virtual source diameter are somewhat offset by the high vacuum required in the electron gun and the fluctuations in the emission current. The thermal-field mode of operation, with its relaxed vacuum requirements and relatively stable emission current has the disadvantage of an increased energy spread of emission, which degrades the spatial resolution of a focused beam. A Schottky point emitter, similar in geometry to a field emitter but with a larger radius, can achieve high current density by use of a low work function surface operating at elevated temperature. In the Schottky emission (SE) mode, electron transmission over the top of the potential barrier rather than tunneling through the barrier is the emission mechanism.

Energy Filtering of Schottky Field Emission Gun Using Fringe Field Monochromator

1999 ◽  
Vol 5 (S2) ◽  
pp. 646-647
Author(s):  
H.W. Mook ◽  
A.H.V. van Veen ◽  
P. Kruit
Keyword(s):  
Field Emission ◽  
Low Voltage ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electron Gun ◽  
Fringe Field ◽  
Objective Lens ◽  
Electronic Band ◽  
Energy Width ◽  
Energy Filtering

The energy resolution which can be attained in electron energy loss spectroscopy (EELS) is determined by the energy spread of the electron source. The energy width of a high brightness electron gun (typically 0.4 to 0.8 eV) blurs the energy spectrum. A pre-specimen energy filter or monochromator must be used to reduce the energy width of the beam below 0.1 eV to allow detailed EELS analysis of the electronic band structures in materials. The monochromator can not only improve EELS, but it is also capable of improving the spatial resolution in low voltage SEM, which is limited by the chromatic blur of the objective lens. A new type of monochromator the Fringe Field Monochromator has been designed and experiments in an ultra high vacuum setup show the monochromatisation of a Schottky Field Emission Gun.

Graphene Nanotubule Cold Field Emission Electron Sources

1994 ◽  
Vol 349 ◽  
Author(s):  
B. H. Fishbine ◽  
C. J. Miglionico ◽  
K. E. Hackett ◽  
K. J. Hendricks
Keyword(s):  
Field Emission ◽  
Current Density ◽  
High Current Density ◽  
High Current ◽  
Field Emitter ◽  
Electron Sources ◽  
Field Emitter Arrays ◽  
Emission Electron ◽  
Emitter Array ◽  
Field Emitter Array

ABSTRACTBuckytubes are considered for high current density cold field emitter array electron sources. They may provide more stable, higher-brightness emission than existing cold field emitter arrays.

8.3: A high aspect ratio, high current density sheet beam electron gun

2010 ◽  
Author(s):  
John E. Atkinson ◽  
Deepika D. Gajaria ◽  
Thomas J. Grant ◽  
Takuji Kimura ◽  
Bradford C. Stockwell ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Current Density ◽  
High Aspect Ratio ◽  
High Current Density ◽  
Electron Gun ◽  
High Current ◽  
Beam Electron

Formation of extremely high current density LaB6 field emission arrays via e-beam deposition

2008 ◽  
Vol 93 (9) ◽  
pp. 093503 ◽  
Author(s):  
K. C. Qi ◽  
Z. L. Lin ◽  
W. B. Chen ◽  
G. C. Cao ◽  
J. B. Cheng ◽  
...  
Keyword(s):  
Field Emission ◽  
Current Density ◽  
High Current Density ◽  
High Current ◽  
Field Emission Arrays ◽  
Beam Deposition

scholarly journals Design and Simulation of a Multi-Sheet Beam Terahertz Radiation Source Based on Carbon-Nanotube Cold Cathode

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1768 ◽  
Author(s):  
Yifan Zu ◽  
Xuesong Yuan ◽  
Xiaotao Xu ◽  
Matthew T. Cole ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Output Power ◽  
Radiation Source ◽  
Low Voltage ◽  
High Current Density ◽  
Electron Gun ◽  
Mode Competition ◽  
Thz Radiation ◽  
Cold Cathode ◽  
Average Output

Carbon nanotube (CNT) cold cathodes are proving to be compelling candidates for miniaturized terahertz (THz) vacuum electronic devices (VEDs) owning to their superior field-emission (FE) characteristics. Here, we report on the development of a multi-sheet beam CNT cold cathode electron optical system with concurrently high beam current and high current density. The microscopic FE characteristics of the CNT film emitter is captured through the development of an empirically derived macroscopic simulation model which is used to provide representative emission performance. Through parametrically optimized macroscale simulations, a five-sheet-beam triode electron gun has been designed, and has been shown to emit up to 95 mA at 3.2 kV. Through careful engineering of the electron gun geometric parameters, a low-voltage compact THz radiation source operating in high-order TM 5 , 1 mode is investigated to improve output power and suppress mode competition. Particle in cell (PIC) simulations show the average output power is 33 W at 0.1 THz, and the beam–wave interaction efficiency is approximately 10%.

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