Multipurpose nanobeam source with supertip emitter

Protrusions of 1 nm dimensions have been grown on single-crystal tips of tungsten and iridium of about 100 nm size. With positive bias the tip can be operated as an intense ion source and with reversed bias intense electron beams can be obtained. In both cases, specific brightness values of up to $1 TA/cm2 srd eV$ have been recorded under optimized conditions. As for gases, tungsten can be used only for less reactive species, such as hydrogen and rare gases, whereas iridium is also useful for aggressive gasses, such as oxygen. Both metals are excellent electron emitters. Thus, a powerful multipurpose source is realized with supertips of tungsten and iridium, as will be demonstrated by a variety of experimental results on their relevant properties.