Carbon "onions" as point electron sources.
The novel type of an electron field emitter is demonstrated by welding a single carbon "onion" onto the end of a tungsten tip inside a high-resolution transmission electron microscope. Such merged structure is found to markedly reduce the onset voltage peculiar to a standard tungsten field emitter due to the small size of the onion and its highly curved surface. Similar to short carbon nanotubes, individual C-onion emitters can sustain large emission currents, more than 100 muA, and exhibit good long-term emission stability. Moreover the insertion of a high electrical resistance in series can suppress the current fluctuation to only 1.9%. All these properties make these newly created field emitters promising candidates for the advanced point electron sources.
Wang
Ming-Sheng
MS
International Centre for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 3050044, Japan. WANG.Mingsheng@nims.go.jp
Golberg
Dmitri
D
Bando
Yoshio
Y