On the atomic arrangement on ZrO/W(100) cathode surface-models for LEED I-V analysis

The work function on W(100) surface (4.6 eV) is remarkably reduced by the peculiar treating process, which consists of two steps. Firstly slight Zr is deposited on the W(100) surface and then it is heat treated in an oxygen environment. After a flash heating in an ultra-high-vacuum condition the treated surface shows very low work function of about 2.7 eV. This surface has been successfully applied to practical thermal field emission cathodes by Swanson's group, however it seems that the reducing mechanism of the work function has not been understood yet. We have been successfully shown that the low work function surface gives a peculiar c(4x2) LEED pattern. For the further analysis of this pattern, I-V (Intensity vs. voltage) analysis is going on.