Lithium Atom Microscopy at Sub-50pm Resolution by R005

To solve modern issues in materials sciences and nanotechnology, aberration corrected electron microscopy has yielded rich results, which could not be realized without a correction technique. Thus, aberration corrected (AC) electron microscopes is obviously becoming "conventional instruments" in transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) for studies of materials and matter. As Feynman and many scientists have dreamed, imaging of individual atom is now reality, but visualizing individual atoms of light elements has yet to be resolved and localization of individual atoms (three dimensional imaging) in matrices has yet to be imaged. Aberration corrected STEM can realize an electron probe as sharp as the diffraction limit, 0.61 / , where is the wavelength of the electrons and is convergent semi-angle of the probe, maximum of which had been determined by geometrical aberrations. Since the scattered intensity of an individual atom in molecules depends on the atomic number (light elements scatter with less intensity than heavy elements), a sharp probe enabled by aberration correction enhances imaging of atoms. Further technical developments of an aberration corrector can detect even individual lithium atom in matter, which has been elusive for electron microscopy and other experimental techniques. Herein we report the development of a new aberration corrected microscope* that achieves a sub-50 pm resolution. The microscope with a cold field emission gun (CFEG) operates at 300 keV and can form a 46 pm electron probe with a 30 mrad semiangle. This new electron microscope, which is named R005 (Resolution double oh five),has allowed us to detect various atoms;lithium, carbon, nitrogen, oxygen, silicon,arsenic, copper, germanium, silicon, gallium,tungsten, and gold in AC-STEM imaging.