Electron-Emission and Flat-Panel Displays

Abstract

When ferroelectrics are subjected to applied electric fields sufficiently large to switch their domains, electrons are emitted from their surfaces [495, 496]. This process is related to the Barkhausen effect, in which the annihilation of two colliding charged 180° domains liberates free charge [497]. Although regarded as a novelty for academic laboratories for many years, more recent work by Gundel et al. [498, 499] has shown that this emission can be synchronized to very fast rise-time electric pulses (ns) and therefore provide a useful pulsed electron source for accelerators. Because of the very short pulse widths, Gundel has achieved very large current densities (of order 1 A/cm²), as shown in Figs. 15.1 and 15.2, using a rather simple structure (Fig. 15.3) with 200 micron grids.