NEW-TYPE OF METAL-ION SOURCE - SURFACE-DIFFUSION LI+ ION-SOURCE

A surface diffusion metal ion source, a new type of metal ion source, is explored. In this device a field desorption process is used to achieve an almost monoenergetic continuous flux of Li+ ions from a [111]-oriented W field emitter. Earlier difficulties with the continuous supply of adatoms, required to produce measurable desorption rates, were overcome by making use of solid state surface diffusion from the Li multilayer reservoir at the shank of the field emitter. The high density of the ion beam (an ion current of 10-12 A was achieved from a W trimer), the extremely narrow energy distribution (full width at half-maximum of 0.25 eV) and the stable geometric form of the emitter itself during the operation are advantages of the new ion source which may be important in different areas of nanotechnology.