Chemical mapping and quantification at the atomic scale by scanning transmission electron microscopy

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Innovative material-growth methods are producing novel low-dimensional materials (e.g., single-atom catalysts, 2D heterostructures).
• Characterizing these materials at the atomic scale requires integrated microscopy and spectroscopy.
• Scanning transmission electron microscopy (STEM) provides exceptional spatial resolution and chemical/electronic sensitivity.

Purpose of the Study:

• To review recent advances in STEM for atomic-scale chemical mapping.
• To discuss the application of energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) in STEM.
• To address the challenge of achieving atomic accuracy in chemical quantification.

Main Methods:

• Utilizing scanning transmission electron microscopy (STEM) for high-resolution imaging.
• Employing energy-dispersive X-ray spectroscopy (EDS) for elemental analysis.
• Applying electron energy loss spectroscopy (EELS) for chemical and electronic state analysis.

Main Results:

• Demonstrated STEM's capability for detailed chemical mapping at the atomic scale.
• Highlighted the synergistic use of EDS and EELS within STEM for comprehensive characterization.
• Identified progress towards accurate chemical quantification at the atomic level.

Conclusions:

• STEM, coupled with EDS and EELS, is a powerful tool for characterizing emerging low-dimensional materials.
• Continued advancements in STEM are crucial for pushing the frontiers of materials research.
• Achieving atomic accuracy in chemical quantification remains a key focus for future development.