Illustrating field emission theory by using plots of transmission probability and barrier strength

This poster is part of a continuing attempt to make field emission theory more transparent. When interpreting current-voltage characteristics related to cold field electron emission (CFE), it is widely assumed that these are controlled and dominated by the behaviour of the tunneling barrier at the emitter/vacuum interface. The transmission probability D for this barrier can be written D ≈ P exp[-G], where P is a transmission pre-factor and G is the JWKB exponent or "barrier strength". The influence of theoretical effects on the barrier form and on D can be illustrated by plotting (-G) and/or lnD as functions of reciprocal field or voltage. This is a specialized form of Fowler-Nordheim (FN) plot. Its usefulness as a pedagogical tool has perhaps been under-appreciated; it may also prove useful for discussing the issue of what causes curvature in FN plots.