Effective field enhancement factor and the influence of emitted space charge
Abstract
Although Fowler and Nordheim developed the basics of field emission nearly one century ago with their introduction of the Fowler-Nordheim equation (FNE), the topic continues to attract research interest particularly with the development of new materials that have been proposed as field emitters. The first order analysis of experiments typically relies upon the FNE for at minimum a basic understand of the physical emission process and its parameters of emission. The three key parameters in the FNE are the work function, emission area, and field enhancement factor, all of which can be difficult to determine under experimental conditions. This paper focuses in particular, on the field enhancement factor β. It is generally understood that β provides an indication of the surface roughness or sharpness of a field emitter cathode. However, in this paper, we experimentally and computationally demonstrate that cathodes with highly similar surface morphologies can manifest quite different field enhancements solely through having different emission regions. This fact can cause one to re-interpret results in which a single sharp emitter is proposed to dominate the emission from a field emitting cathode.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 24, 2015
- Source ID
- 10.1063/1.4929364
Entities
People
- D. Shiffler
- J. R. Harris
- John Petillo
- Ken Golby
- Kevin L. Jensen
- Matthew Lacour
- Wilkin Tang
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory
- United States Naval Research Laboratory
- United States Navy Reserve