Quantitative atomic 3-D imaging of single/double sheet graphene structure

Graphene sheets can be regarded as base structure of many carbon nanostructures, and atomic arrangements and variations in the atomic structure have a drastic impact on their unique properties. Using a single/double layer graphene model structure, we present a strategy to “see” single carbon atoms in 3-D. In high-resolution transmission electron microscopy, exit-wave images are essential to obtain and to understand 3-D atomic structure. Using electrons at 80 kV not only minimizes the knock-on damage, but also improves the detection sensitivity due to the higher scattering power of carbon at lower acceleration voltage of the electron. Using experiments and image simulations, positions of individual carbon atoms in a single/double layer structure in graphene have been identified.

The figure shows an exit-wave phase image of a single/double sheet graphene structure-reconstructed from a through-focal series of high-resolution transmission electron microscope lattice images. Single carbon atoms are clearly resolved. The insets show magnified images of the atomic arrangement of individual carbon atoms in the single graphene sheet and in the double atomic graphene sheet. This enables a quantitative atomic analysis in 3-D.Figure optionsDownload as PowerPoint slideResearch highlights
► Unprecedented view of the atom arrangement in graphene.
► A strategy to “see” single atoms in 3-D.
► Identification of positions of individual carbon atoms in a single/double layer structure in graphene.
► Quantitative understanding of this atom arrangement.