Calibrating the atomic balance by carbon nanoclusters

TL;DR

This paper introduces a method to count carbon atoms with near atomic precision using a calibrated electron microscope and nanocluster standards, enabling detailed analysis of thin graphene layers.

Contribution

It presents a novel calibration technique using carbon nanoclusters for precise atomic counting in electron microscopy.

Findings

Achieved linear calibration from a few to 34,000 atoms

Enabled visualization of sub-100 nm graphene sheets

Provided quantitative measurements beyond optical and scanning probe limits

Abstract

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 thin layers of stacked graphene sheets. Suspended sheets with a thickness below 100 nm are visualized, providing quantitative measurement in a regime inaccessible to optical and scanning probe methods.