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

Published online by Cambridge University Press:  01 February 2011

Feng Jin ,
Yan Liu ,
Scott A Little  and
Chris M Day
Feng Jin
Affiliation:
[email protected], Ball State University, Phsyics and Astronomy, Muncie, Indiana, United States
Yan Liu
Affiliation:
[email protected], Ball State University, Phsyics and Astronomy, Munice, Indiana, United States
Scott A Little
Affiliation:
[email protected], Ball State University, Phsyics and Astronomy, Muncie, Indiana, United States
Chris M Day
Affiliation:
[email protected], Ball State University, Phsyics and Astronomy, Muncie, Indiana, United States
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Abstract

We 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.

Keywords

chemical vapor deposition (CVD) (deposition)coatingthin film
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1142: Symposium JJ – Nanotubes, Nanowires, Nanobelts and Nanocoils–Promise, Expectations and Status , 2008 , 1142-JJ15-41
Copyright
Copyright © Materials Research Society 2009

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References

REFERENCES

1. De Jonge, N, Bonard, JM. Carbon nanotube electron sources and application. Phil Trans R Soc Lond A 2004; 362(1823):2239–2266.10.1098/rsta.2004.1438Google Scholar
2. De Jonge, N, Brightness of carbon nanotube electron sources. J Appl Phys 2004; 95(2):673–681 Google Scholar
3. De Heer, WA, Chatelain, A, Ugarte, D. A carbon nanotube field-emission electron source. Science 1995; 270:1179–1180 Google Scholar
4. Cheng, Y, Zhou O., Electron field emission from carbon nanotubes. C R Physique 2003; 4:1021–1033 Google Scholar
5. Cox, DC, Forrest, RD, Smith, PR, Silva, SR P. Thermionic emission from defective carbon nanotubes. Appl Phys Lett 2004; 85(11):2065–2067 Google Scholar
6. Shiraishi, M, Ata, M. Work function of carbon nanotubes. Carbon 2001; 39(12):1913–1917 Google Scholar
7. Jin, F, Liu, Y, Day, CM. Thermionic emission from carbon nanotubes with a thin layer of low work function barium strontium oxide surface coating. App Phys Lett 2006; (88):163116 1–3.Google Scholar