Atomic Resolution Electron Diffraction Imaging of Metallic Nanoclusters
Microscopy and Microanalysis
Imaging non-crystalline objects at atomic-resolution, such as macromolecules or individual nanoclusters, remains as a significant challenge for electron microscopy. With the development of C s correctors, the image resolution of electron microscopes is significantly improved . However, information that can be obtained from electron images is still limited by loss of contrast due to electron energy spread and limited coherence . In comparison, electron diffraction imaging, a recently
... g, a recently developed technique, takes advantage of the high resolution information available in oversampled diffraction patterns, and combines with iterative algorithms to retrieve the missing phases and reconstruct the object images beyond the aberration limits . The resolution is only limited by diffraction intensity. The recent work by Wu and Spence shows one such example for a 13nm diameter Au particle . Here we explore the possibility of applying the diffraction imaging technique to image the structures of small (5 nm or smaller) metallic nanoclusters, for which improving image resolution and contrast and limiting electron beam induced structural changes are all critical issues To demonstrate the feasibility of electron diffraction imaging for small metal particles, a computer diffraction experiment is conducted on a 4nm-sized Au icosahedral nanocluster (Fig.