Demountable single-atom electron source

Abstract

We report emission properties of single-atom tips, noble electron sources terminated with a single atom. The repairing function of the sources, which had been already demonstrated by using field ion microscope [Fu, et al. Phys. Rev. B 64, 113401 (2001)], was confirmed by using field emission microscopy, and in addition, the demountable character was demonstrated repeatedly. The brightness of the collimated beam emitted from the single-atom tips was estimated to be an order of 1010 A/cm2/str. (E ∼ 2 keV), which is two orders of magnitude higher than those of the conventional field emission sources. There appeared an extra shoulder in the energy spectra, which is strongly correlated with a single-atom ended structure. The fluctuation of the emission current exhibited step-and spike-like noises, which were typical features of nano-electron sources. The single-atom sources are promising candidates of the electron sources in high-performance electron-beam instruments. © 2005 The Surface Science Society of Japan.