Thermionic Emission Spectroscopy of Metals

Abstract

We know (see Chapter 1) that at sufficiently high temperatures, a small fraction of the electrons in a metal have energies higher than the maximum of the potential barrier at the surface and some of them escape from the metal giving rise to a thermionic current. The potential barrier is shown (schematically) in Fig. 9.1. On the vacuum side of the interface at distances larger than 4 Å or so from the top layer of atoms the electron moves in a potential field described by (see Section 1.3)

$$v(z) \simeq \frac{{ - {e^2}}}{{4z}} - eFz + {E_F} + \phi $$

(9.1)