Work function changes of W(110) with temperature and Sm adsorption using electron beam retarding potential technique

We have studied the work function changes (ΔΦ) of W(110) by Sm adsorption as a function of Sm thickness at room temperature and also that of the Sm-covered W(110) as a function of temperature. The work function change was monitored using the electron beam retarding potential technique in conjunction with low energy electron diffraction (LEED). It is found that the work function of W(110) decreases rapidly at lower dose (0.75 Å) of Sm, touches a minima (ΔΦ=0.32 eV), then increases slightly and is saturated with further Sm dosing. Besides, it was also found that the work function of W(110) reduces by 0.3 eV at a particular dose of Sm with substrate temperature up to 523 K. These results show a strong dependence of the work function of W(110) on its temperature and adsorption of Sm and this can be used to advantage in the making of emitters.