Electron emission mechanism of scandium-tungsten cathodes

Scandium-tungsten (Sc-W) cathodes have garnered a lot of research attention due to their high emission current density. This study investigates the electronic properties of Sc-W cathodes using the VASP code to explain the operating mechanism of hot electron emission. The results reveal that the work function is decreased by 0.58 eV, whereas the charge density in the crystal structure, the number of high valence electrons and the energy of electrons increase when Sc content is increased from 1% to 2%. Moreover, the bandgap and energy required for electrons to jump from the valence band to the conduction band decreased with the increase of Sc content, enhancing the current emission density and reducing the work function of the cathode.