Abstract
We describe the new coherent nano‐area electron diffraction (NED) and its application for structure determination of individual nanostructures. The study is motivated by the challenge and the general lack of analytical techniques for characterizing nanometer‐sized, heterogeneous phases. We show that by focusing electrons on the focal plane of the pre‐objective lens using a 3rd condenser lens and a small condense aperture, it is possible to achieve a nanometer‐sized highly parallel illumination or probe. The high angular resolution of diffraction pattern from the parallel illumination allows over‐sampling and consequently the solution of phase problem based on the recently developed ab initio phase retrieval technique. From this, a high‐contrast and high‐resolution image can be reconstructed at resolution beyond the performance limit of the image‐forming objective lens. The significance of NED for nanostructure characterization will be exemplified by single‐wall carbon nanotubes and small metallic clusters. Imaging from diffraction patterns, or diffractive imaging, will be demonstrated using double‐wall carbon nanotubes. Microsc. Res. Tech. 64:347–355, 2004. © 2004 Wiley‐Liss, Inc.