Diffraction microscopy using 20 kV electron beam for multiwall carbon nanotubes

Diffraction microscopy with iterative phase retrieval using a 20 kV electron beam was carried out to explore the possibility of high-resolution imaging for radiation-sensitive materials. Fine, homogeneous, and isolated multiwall carbon nanotubes (MWCNTs) were used as specimens. To avoid lens aberrations, the diffraction patterns were recorded without a postspecimen lens. One- and two-dimensional iterative phase retrievals were executed. Images reconstructed from the diffraction pattern alone showed a characteristic structure of MWCNTs with the finest feature corresponding to a carbon wall spacing of 0.34 nm