Sub-Angstrom electron imaging
The sub-Angstrom resolution was achieved using FEI’s Tecnai F20 ST transmission electron microscope, using advanced electron optics capabilities developed by FEI and its partner, Corrected Electron Optical Systems (CEOS) of Heidelberg, Germany. CEOS develops advanced correction systems for high-resolution electron microscopy.
Dr Max Haider, co-founder and managing director of CEOS, reports: "A long-time ongoing dream, to achieve sub-Angstrom resolution, has now been attained with a 200kV TEM equipped with a Cs-corrector developed by CEOS and a monochromator developed by FEI." Cs-correction refers to correction of spherical aberration. CEOS uses hexapoles in an arrangement with additional round lenses.
The equipment is able to implement novel TEM techniques such as 3D reconstruction with tomography, scanning probe applications or in situ observation of specimen responses to variations in temperature, stress or chemical environment, all with sub-Angstrom resolutions.
"The successful use of an electron beam monochromator to improve the resolution of a Cs-corrected electron microscope marks a major milestone for the field of electron microscopy," says Dr Michael O’Keefe of the US National Center of Electron Microscopy in Berkeley, California. "Theory has long predicted that a monochromator would be able to push the resolution of the super-twin lens beyond the 1.4Angstrom resolution demonstrated with Cs-correction alone. However, the difficulties involved in implementation of a monochromator without compromising the imaging qualities of the electron beam are well known. FEI deserves to be congratulated for this outstanding achievement."
Professor Dr Hannes Lichte of Dresden University in Germany, comments: "For the first time, the authors convincingly show that in a Cs-corrected TEM by additional reduction of energy spread using a gun monochromator, they extend the total information limit to significantly better than 0.1nm. As evident from their diffractograms, they are not far off the theoretical limit of about 0.07nm in at least some direction. Congratulations!"
Dr Rob Fastenau, senior vice president of FEI’s Electron Optics division, says "FEI was the first to combine TEM with Cs-correctors in the late 90s and was the first in 2000 with proven monochromator technology."
FEI Electron Optics is based in Eindhoven, The Netherlands.
