The pre-exponential voltage-exponent as a sensitive test parameter for field emission theories.
For field electron emission (FE), an empirical equation for measured current I m as a function of measured voltage V m has the form I m = CV m  exp[-B/V m], where B is a constant and C and k are constants or vary weakly with V m. Values for k can be extracted (i) from simulations based on some specific FE theory, and in principle (ii) from current-voltage measurements of sufficiently high quality. This paper shows that a comparison of theoretically derived and experimentally derived k-values could provide a sensitive and useful tool for comparing FE theory and experiment, and for choosing between alternative theories. Existing methods of extracting k-values from experimental or simulated current-voltage data are discussed, including a modernized 'least residual' method, and existing knowledge concerning k-values is summarized. Exploratory simulations are reported. Where an analytical result for k is independently known, this value is reliably extracted. More generally, extracted k-values are sensitive to details of the emission theory used, but also depend on assumed emitter shape; these two influences will need to be disentangled by future research, and a range of emitter shapes will need examination. Other procedural conclusions are reported. Some scientific issues that this new tool may eventually be able to help investigate are indicated.
['Forbes|R G|RG|0000-0002-8621-3298', 'Popov|E O|EO|', 'Kolosko|A G|AG|', 'Filippov|S V|SV|']
field electron emission empirical field emission equation field electron emission theory–experiment comparisons least-residual method local-gradient method pre-exponential voltage exponent