Sub-Angstrom high-resolution transmission electron microscopy at 300 keV.

Sub-(A) over circle ngstrom transmission electron microscopy has been achieved at the National Center for Electron Microscopy (NCEM) by a one-(A) over circle ngstrom microscope (OAM) project using software and enhanced hardware developed within a Brite-Euram project (Ultramicroscopy 64 (1996) 1). The NCEM O (A) over circleM provides materials scientists with transmission electron microscopy at a resolution better than 1 Angstrom by using extensive image reconstruction to exploit the significantly higher information limit of an FEG-TEM over its Scherzer resolution limit. Reconstruction methods chosen used off-axis holograms and focal series of underfocused images. Measured values of coherence parameters predict an information limit of 0.78 Angstrom. Images from a [110] diamond test specimen show that sub-Angstrom resolution of 0.89 Angstrom has been achieved with the OAM using focal series reconstruction. (C) 2001 Elsevier Science B.V. All rights reserved.