Calibrating the atomic balance by carbon nanoclusters

摘要

Carbon atoms are counted at near atomic-level precision using a scanning transmission electron microscope calibrated by carbon nanocluster mass standards. A linear calibration curve governs the working zone from a few carbon atoms up to 34 000 atoms. This linearity enables adequate averaging of the scattering cross sections, imparting the experiment with near atomic-level precision despite the use of a coarse mass reference. An example of this approach is provided for layer counting of stacked graphene sheets. Suspended graphene sheets with a size below 100 nm are visualized, providing quantitative measurement in a regime inaccessible to optical and scanning probe methods.