Evaporation and thermionic emission processes of Pb/W(110) have been studied in situ by emission electron microscopy (EEM). By the photoemitted EEM, the evaporation of Pb except the first layer has been observed In situ at 603-673 K, resulting in an increase in the work function that prevents photoemission of electrons. By heating to 1200 K, the surface can be again imaged by EEM even without illumination, i.e., thermionic emission electron microscopy (TEEM). This TEEM observation at lower temperatures than usual becomes possible owing to thermionic emission assisted by the electric field between the objective lens and the surface.
- Photoemission electron microcopy
- Thermionic emission electron microscopy