Work Function Measurement of Modified Tungsten Surface by Use of Photoemission Electron Microscope

ZrO₂ powder dissolved into ethanol on the surface of polycrystalline and single crystal tungsten sheets are characterized using photoemission electron microscopy. Local photo current estimated from the brightness at the screen is plotted against the photon energy. The estimated work function for several samples ranges from 2.80-2.92 eV. Although the method is very simple and convenient, it contains a lot of ambiguity and includes sample temperature effect. The work function can be estimated from the shift of the experimental curve from the calculated curve. It can be concluded that the reported value 2.7 eV of the work function of ZrO-W(100) due to Fowler Nordhiem plot is similar to the optically determined values