Desorption of the C2- anion from the Au-C-deposited Y2O3-Stabilized ZrO2 surface

Carbon dimer anions (C 2 - ) and atomic oxygen radical anions (O - ) desorbed from an Au-C-deposited Y 2 O 3 -stabilized ZrO 2 (YSZ) surface have been observed. Both the emitted anions and electrons were found to be strongly dependent on the surface temperature and applied extraction field. The Arrhenius plots for the anions and electrons exhibit double-linear behavior, resulting in lower apparent activation energies in the high-temperature region (>913 K). It was found that the apparent activation energies can be reduced by the extraction field. Measurements of the absolute emission current density show similar temperature and field features as derived by TOF (time-of-flight) spectroscopic investigations. The observed anions of O - are attributed to the detachment of the transient anions of O 2 (s) (i.e., O 2 - (s) → O - (s) + e - (s)), which migrate from the YSZ bulk onto the emission surface. The C 2 -(s) anions are attributed to the surface anion-exchange reactions between O - (s) and surface carbon atoms. An emission mechanism is proposed to account for the observed temperature dependence, field characteristics, and emission branch ratios of the desorbed anions and electrons.