Current Saturation in Semiconductor and Semimetallic Field Emitters

AbstractWe report an effective procedure for fabricating carbon nanotube emitters by directly synthesizing carbon nanotubes on an electrochemically sharpened tungsten tip. The nanotubes adhere very well to the tip of tungsten without any painting materials. Thermal cleaning of the tungsten tip under applied electric field reduced the number of nanotubes formed on the tip resulting in a single nanotube emitter. Electron field emission properties were investigated by employing a field emission microscope with a base pressure ~ 1 × 10-9 Torr. The emission images with respect to the applied field and time were obtained. Different emission images consisting of one to four lobes at different applied fields were observed. The characteristic of the emission current vs. applied voltage was analyzed. Applied potentials up to 3000 V were tested. The estimated field on the emitter was on the order of several tens of volts per nanometer. Our investigation suggests that at lower fields, the I-V characteristic of the nanotube emitter follows Fowler-Nordheim (F-N) emission behavior. At higher applied field, current saturation was observed.

Download Full-text

Current saturation mechanisms in carbon nanotube field emitters

Applied Physics Letters ◽

10.1063/1.125758 ◽

2000 ◽

Vol 76 (3) ◽

pp. 375-377 ◽

Cited By ~ 340

Author(s):

Kenneth A. Dean ◽

Babu R. Chalamala

Keyword(s):

Carbon Nanotube ◽

Field Emitters ◽

Current Saturation

Download Full-text

Origin of the current saturation level of p-doped silicon field emitters

Journal of Vacuum Science & Technology B Nanotechnology and Microelectronics Materials Processing Measurement and Phenomena ◽

10.1116/6.0001554 ◽

2022 ◽

Vol 40 (1) ◽

pp. 013203

Author(s):

Simon Edler ◽

Andreas Schels ◽

Florian Herdl ◽

Walter Hansch ◽

Michael Bachmann ◽

...

Keyword(s):

Saturation Level ◽

Field Emitters ◽

Current Saturation ◽

Doped Silicon

Download Full-text

FIELD EMISSION AND APPLICATION OF CARBON NANOTUBES

NANO ◽

10.1142/s1793292007000465 ◽

2007 ◽

Vol 02 (02) ◽

pp. 69-89 ◽

Cited By ~ 26

Author(s):

SEONG CHU LIM ◽

KYU LEE ◽

IL HA LEE ◽

YOUNG HEE LEE

Keyword(s):

Carbon Nanotubes ◽

Field Emission ◽

Field Enhancement ◽

Current Status ◽

Field Emission Display ◽

X Ray ◽

Field Emitters ◽

Current Saturation ◽

Potential Applications ◽

Current Emission

The mechanism of field emission from a metal surface was well explained based on the quantum mechanics in early 20th century. Since then, various materials have been studied for field emitters. However, so far, we have been using only limited materials as a field emitter and an application in some area requires further scientific understandings and technological advancements. In this paper, we review the current status of researches in field emission and emission phenomena of carbon nanotubes (CNTs). This may include current saturation induced by gas adsorbates, screening effects, high current emission, degradation of emitter, and field enhancement factor. We also introduce the present status in the development of various CNT-based field emission devices and discuss their performances. In this part, various potential applications such as field emission display, ionization gauge, X-ray gun, and lamp will be presented.

Download Full-text

Characteristics and Application of Temperature-Field Emitters

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100114347 ◽

1975 ◽

Vol 33 ◽

pp. 144-145

Author(s):

N. Tamura ◽

T. Goto ◽

Y. Harada

Keyword(s):

Temperature Field ◽

Electron Microscope ◽

Field Emission ◽

Resolving Power ◽

High Brightness ◽

Field Emitters ◽

Emission Electron ◽

Sufficient Stability ◽

Scanning Electron ◽

Illuminating System

On account of its high brightness, the field emission electron source has the advantage that it provides the conventional electron microscope with highly coherent illuminating system and that it directly improves the, resolving power of the scanning electron microscope. The present authors have reported some results obtained with a 100 kV field emission electron microscope.It has been proven, furthermore, that the tungsten emitter as a temperature field emission source can be utilized with a sufficient stability under a modest vacuum of 10-8 ~ 10-9 Torr. The present paper is concerned with an extension of our study on the characteristics of the temperature field emitters.

Download Full-text

Design of a Field-Emission Gun for the Phillips CM20/STEM microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134090 ◽

1990 ◽

Vol 48 (2) ◽

pp. 100-101

Author(s):

P.M. Mul ◽

B.J.M. Bormans ◽

L. Schaap

Keyword(s):

High Resolution ◽

Field Emission ◽

Analytical Electron Microscopy ◽

Emission Region ◽

Attractive Alternative ◽

Electron Holography ◽

Field Emitter ◽

Field Emitters ◽

Resolution Electron ◽

High Resolution Tem

The first Field Emission Guns (FEG) on TEM/STEM instruments were introduced by Philips in 1977. In the past decade these EM400-series microscopes have been very successful, especially in analytical electron microscopy, where the high currents in small probes are particularly suitable. In High Resolution Electron Holography, the high coherence of the FEG has made it possible to approach atomic resolution.Most of these TEM/STEM systems are based on a cold field emitter (CFE). There are, however, a number of disadvantages to CFE’s, because of their very small emission region: the maximum current is limited (a strong disadvantage for high-resolution TEM imaging) and the emission is unstable, requiring special measures to reduce the strong FEG-induced noise. Thermal field emitters (TFE), i.e. a zirconiated field emitter source operating in the thermal or Schottky mode, have been shown to be a viable and attractive alternative to CFE’s. TFE’s have larger emission regions, providing much higher maximum currents, better stability, and reduced sensitivity to vacuum conditions as well as mechanical and electrical interferences.

Download Full-text