Realization of an axially aligned Au-ion source of atomic size

Nanotips are high-brightness electron sources with a principal characteristic source-size of one atom. We explore here nanotips as a type of atom-size source of Au ions. Conditions were found for a reproducible fabrication of a single Au nanotip on the principal axis of a W-base tip that emitted a beam of Au exclusively from its apex. The measured source characteristics were (i) the atomic-size source; (ii) currents: 10−14–1012 A; (iii) stability: 5 h; (iv) beam opening angle: 3.2°; and (v) energy dispersion <1 eV. First focusing experiments showed crossover and that the entire emitted beam was focused.