Application of phase extension method to sub-Å transmission electron microscopy

A sub-Å resolution analysis of a Si crystal structure was performed successfully using a phase extension technique that combined the high-voltage electron microscopy (HVEM) and energy-filtered precession electron diffraction (EF-PED) methods. The high resolution electron microscopy (HREM) image of Si [211] was obtained with a spatial resolution of 0.12 nm using HVEM. The electron diffraction of Si [211] was acquired with a spatial resolution of 0.06 nm by employing the EF-PED method. The phase information of Si [211] was extracted from a deconvoluted image by applying instrumental parameters. Its amplitude information with higher spatial resolution was quasi-kinematically extracted from EF-PED data. Finally, it was revealed that Si atoms were clearly separated with a resolution of 0.78 Å in the enhanced resolution image. Therefore, it is expected that the combination of the HVEM and EF-PED methods will be a useful and powerful tool for the quantitative characterization of nanostructured materials.