The role of electrode material and polarization fatigue on electron emission from ferroelectric Pb(ZrxTi1-x)O3 cathodes

Electron emission from bulk Pt/PZT/Pt and RuO2/PZT/RuO2 ferroelectric cathodes is reported. The total emission current (0.8 A) and polarization fatigue are high for ferroelectric cathodes with Pt electrodes, while emission current (0.18 A) and polarization fatigue are significantly lower for cathodes with RuO2 electrodes. The data correlate with earlier results from research on ferroelectric memories, which suggest that oxygen vacancies near the electrode/ferroelectric interface and through the bulk of the ferroelectric layer play a major role in controlling the polarization switching of PZT-based capacitors and consequently in controlling the electron emission process in PZT cathodes. The strong correlation between polarization fatigue and emission observed in the present investigation provides evidence for the role of polarization inversion on the electron emission phenomenon. In addition, the data provide evidence for the role that oxygen vacancies play in controlling electron emission from PZT cathodes. (C) 2000 American Institute of Physics. [S0003-6951(00)00843-3].