화학공학소재연구정보센터
Nature Materials, Vol.8, No.10, 808-812, 2009
Imaging single atoms using secondary electrons with an aberration-corrected electron microscope
Aberration correction has embarked on a new frontier in electron microscopy by overcoming the limitations of conventional round lenses, providing sub-angstrom-sized probes(1-8). However, improvement of spatial resolution using aberration correction so far has been limited to the use of transmitted electrons both in scanning and stationary mode, with an improvement of 20-40% (refs 3-8). In contrast, advances in the spatial resolution of scanning electron microscopes (SEMs), which are by far the most widely used instrument for surface imaging at the micrometre-nanometre scale(9), have been stagnant, despite several recent efforts(10,11). Here, we report a new SEM, with aberration correction, able to image single atoms by detecting electrons emerging from its surface as a result of interaction with the small probe. The spatial resolution achieved represents a fourfold improvement over the best-reported resolution in any SEM (refs 10-12). Furthermore, we can simultaneously probe the sample through its entire thickness with transmitted electrons. This ability is significant because it permits the selective visualization of bulk atoms and surface ones, beyond a traditional two-dimensional projection in transmission electron microscopy. It has the potential to revolutionize the field of microscopy and imaging, thereby opening the door to a wide range of applications, especially when combined with simultaneous nanoprobe spectroscopy.