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This paper discusses issues relating to the current-voltage characteristics of large-area field electron emitters (LAFEs). It forms part of a continuing project to investigate how the statistical distribution of individual-emitter characteristics affects the interpretation of Fowler-Nordheim plots taken from the LAFE as a whole. It is assumed that tunneling takes place through a Schottky-Nordheim...
As part of a longer-term project to compare different methods of extracting emission-area data from ideal Fowler-Nordheim plots, this Poster investigates refinements to the extraction-parameter approach. It is shown that varying the choice of the scaled fitting parameter ft, depending on the range of values used for the independent variable, does make a noticeable difference. However, the (usually...
This tutorial lecture provides an introduction (suitable for those relatively new to the subject) to methods available for the extraction of emitter characterization data from field electron emission (FE) current-voltage data, to the problems of doing this reliably, and to some recent progress in developing better understanding of the issues involved.
With a large-area field electron emitter, when an individual post-like emitter is sufficiently resistive, and current through it sufficiently large, then voltage loss occurs along it. This conference presentation provides a simple analytical and conceptual demonstration that this voltage loss is directly and inextricably linked to a reduction in the field enhancement factor (FEF) at the post apex,...
Using numerical simulations based on finite-element techniques, this work investigates the electrostatic interaction (“mutual shielding”) between two emitters each modeled as a cylindrical post capped with a hemisphere (the “HCP” model). The interaction between two adjacent emitters has recently been investigated in [8, 11], using different models. Reference [8] used the (analytical) “floating spheres...
This Poster outlines simple general derivations of the correction factors λT=πp/sin(πp) and λF=πq/sin(πq) that first appeared in this form in the 1973 re-formulation by Swanson and Bell of equations originally derived by Murphy and Good in 1956. The original proofs and results apply only to the Schottky-Nordheim barrier. For planar smooth-surface conceptual models, analyzed via the Kemble approach,...
This conference paper provides an overview of the material presented in two field electron emission tutorial lectures given at the 2016 Young Researcher's School in Vacuum Micro- and Nano- Electronics, held in Saint-Petersburg in October 2016. The powerpoint presentations themselves [1, 2] will be mounted on ResearchGate. This paper aims to indicate the scope and structure of the tutorials, and also...
This conference presentation is part of continuing work to clarify the theory of cold field electron emission (CFE). It addresses the issue that some general physics textbooks and many published experimental papers use one or more CFE equations that are known to CFE theoreticians to be defective. These defective equations have been in wide use for 15 years or more: they impede the interpretation of...
This conference poster introduces changes in the terminology used to present Fowler-Nordheim (FN) theory. The underlying aim is to make theoretical discussion more scientific.
This conference poster presents the results of a re-derivation, using the modern International System of Quantities (i.e., mksa equations), of a formula for the rate-constant for the electrostatic field ionization (ESFI) of a hydrogen atom. This problem was first examined many years ago by Landau and Lifshitz, but their atomic units proof did not generate a formula of the kind required in modern technological...
This conference poster presents an engineering ansatz that may be useful in situations where an orthodoxy test on the related Fowler-Nordheim plot has suggested that an extracted apparent field enhancement factor (FEF) βapp is spuriously large. The ansatz, called phenomenological adjustment, converts βapp to a smaller “ansatz-corrected” value βazc that can be presumed to be closer to the true macroscopic...
This conference poster reports two improved methods of extracting area-like information from measured current-voltage [im(Vm)] characteristics for cold field electron emission (CFE). Results are valid only if the emission situation is orthodox. These methods: (a) confirm “by experiment” the long-held theoretical expectation that in CFE theory the Schottky-Nordheim (SN) barrier is a better physical...
This conference poster present an alternative derivation of a well known formula that relates both to the concept of reduced brightness in a charge-particle (CP) beam and to the blurring of field-ion image spots. It is then argued that field ion images provide a practical illustration of some aspects of CP optics, including the issue of whether reduced brightness is always a conserved quantity.
This conference poster comments on the reliability of a recently published book on the topic of “Fowler-Nordheim Field Emission: Effects in Semiconductor Nanostructures”. The precise origin of important equations in the book is unclear, and one important equation checked apparently does not reduce to a Fowler-Nordheim-type equation in circumstances where it ought to do so. It is concluded that the...
This conference presentation comments on the recent report of nearly-exact voltage scaling, in field electron emission measurements made when a single-tip emitter faces an extended planar surface. An alternative, “intuitive”, explanation is offered for this effect, and supplements the more quantitative explanations presented in the literature.
Most Fowler-Nordheim plots are analyzed using orthodox or elementary theory. If emission situations are not orthodox, results may be spurious. An FN-plot-based test has been devised for deciding when emission systems are not orthodox. This poster describes how to use a spreadsheet to apply the test, and presents specimen results.
This paper has three related aims. First, it argues that there is a need for a carefully formulated and properly established body of field electron emission science. Second, it outlines what this body of science should include. Third, it reports on progress on putting this science into place.
This work demonstrates error in the definition of voltage given in International Standards. This definition does not coincide with the quantity "practical voltage" measured by national standards laboratories. The physical arguments that show this also have implications for the theoretical understanding of patch fields and of electron emission from semiconductors.
Cabrera et al. have reported and explained a voltage-scaling effect, as distance d between an emitter and plane varies. An alternative approach here splits the explanation into parts related to the emission physics and the system electrostatics, and has advantages. The basic need is to keep a characteristic field constant.
This paper reports progress in developing an integrated theory of field emitter optics that covers both electron and ion emission (including liquid metal ion sources and atom probe tomography). Issues covered include resolution theory, Hawkes-Kasper angular magnification, discrepancies in brightness theory, and whether reduced brightness really is a conserved quantity.
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