Self focusing of field emitted electrons at an ellipsoidal tip

Kyritsakis, A.; Kokkorakis, G. C.; Xanthakis, J. P.; Kirk, T. L.; Pescia, D.
July 2010
Applied Physics Letters;7/12/2010, Vol. 97 Issue 2, p023104
Academic Journal
In models of field emission the needle is usually terminated by a hemispherical cap. Here we choose to terminate it with a hemiellipsoidal cap and use a three-dimensional Wentzel–Kramers–Brillouin method for the computations. This has two important consequences: as the ellipsoid becomes more elongated, (a) the effective emission area is decreased and (b) the quantum mechanically computed electron paths converge toward the needle axis. Both mechanisms produce a self-focusing of the field emitted electrons.


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