Study of grain boundary diffusion of potassium in gold films using a clean, controlled, and localized source of alkali atoms

Grain boundary diffusion of K in polycrystalline Au films has been studied by the Auger surface accumulation method. A novel diffusant source which is clean, controlled, and localized was used. The Au film was deposited on a KCl substrate and an electron beam was sent through the Au film. K was then generated by electron impact dissociation of KCl. The value of the diffusion constant obtained is (K′δ/δ′)D_b = (1.6±1.1)×10⁻¹³ cm² s⁻¹.