Discrete space charge affected field emission: Flat and hemisphere emitters
Abstract
Models of space-charge affected thermal-field emission from protrusions, able to incorporate the effects of both surface roughness and elongated field emitter structures in beam optics codes, are desirable but difficult. The models proposed here treat the meso-scale diode region separate from the micro-scale regions characteristic of the emission sites. The consequences of discrete emission events are given for both one-dimensional (sheets of charge) and three dimensional (rings of charge) models: in the former, results converge to steady state conditions found by theory (e.g., Rokhlenko et al. [J. Appl. Phys. 107, 014904 (2010)]) but show oscillatory structure as they do. Surface roughness or geometric features are handled using a ring of charge model, from which the image charges are found and used to modify the apex field and emitted current. The roughness model is shown to have additional constraints related to the discrete nature of electron charge. The ability of a unit cell model to treat field emitter structures and incorporate surface roughness effects inside a beam optics code is assessed.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 19, 2015
- Source ID
- 10.1063/1.4921186
Entities
People
- D. Shiffler
- I. M. Rittersdorf
- J. R. Harris
- J.W. Luginsland
- Joel Lebowitz
- John Petillo
- Kevin L. Jensen
- Wilkin Tang
- Y. Y. Lau
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory
- National Academy of Sciences
- Rutgers University
- United States Naval Research Laboratory
- United States Navy Reserve
- University of Michigan