Dynamic Change of the Work Function of Plasma Electrode Materials due to Hydrogen Plasma exposure

Abstract

Abstract It has been known that the work function of plasma electrode (PE) surfaces such as Cs-covered Mo and C12A7-electride can be decreased when the surfaces are immersed in hydrogen (or deuterium) plasma. We discovered that the work function of the C12A7-electride changed right after the termination of plasma exposure with the time constant of a few minutes. This phenomenon was not observed on the surface of clean metals (Mo or Ta). By extrapolating the dependence of work function against time to determine the value at the plasma termination, the work function during plasma exposure was estimated to be 2.4 – 2.5 eV, which can be compared with the value of the electride exhibiting metallic conductivity.