Konopsky V.N., Letokhov V.S.
Towards direct observation of atomic structure of biomolecules with nanometer spatial resolution by visible light. // Laser Physics, 1997, V.7, P.173-178.

We describe a single-atom source of electrons of a new type based on resonant tunneling of electrons from Si needles through a thin epitaxial film of CaF_2 coating via the levels of dopant Sm ions in this coating. The results of the fist experiments on the implementation of such a source are presented. We consider the possibility to apply such a single-atom source of electrons as an active element for an electron-fluorescence spectromicroscope that would simoltaniously possess subnanometer spatial resolution and chemical selectivity.


Fig.4 Possible application of the one-atom electron source for spectroscopy with the subwavelength spatial resolution.