Advances and Applications of Atomic-Resolution Scanning Transmission Electron Microscopy

Although scanning transmission electron microscopy (STEM) images of individual heavy atoms were reported 50 years ago, the applications of atomic-resolution STEM imaging became wide spread only after the practical realization of aberration correctors on field-emission STEM/TEM instruments to form sub-Angstrom electron probes. The innovative designs and advances of electron optical systems, the fundamental understanding of electron-specimen interaction processes, and the advances in detector technology all played a major role in achieving the goal of atomic-resolution STEM imaging of practical materials. It is clear that tremendous advances in computer technology and electronics, image acquisition and processing algorithms, image simulations, and precision machining synergistically made atomic-resolution STEM imaging routinely accessible. It is anticipated that further hardware/software development is needed to achieve three-dimensional atomic-resolution STEM imaging with single-atom chemical sensitivity, even for electron-beam-sensitive materials. Artificial intelligence, machine learning, and big-data science are expected to significantly enhance the impact of STEM and associated techniques on many research fields such as materials science and engineering, quantum and nanoscale science, physics and chemistry, and biology and medicine. This review focuses on advances of STEM imaging from the invention of the field-emission electron gun to the realization of aberration-corrected and monochromated atomic-resolution STEM and its broad applications.

Automated summary

Advances in atomic-resolution STEM imaging have been driven by innovative designs in electron optical systems, developments in detector technology, improvements in image acquisition and processing algorithms, and advancements in precision machining. These factors have not only made atomic-resolution STEM imaging more accessible in practical materials research, but also indicate a growing need for further hardware and software development to achieve three-dimensional atomic-resolution STEM imaging with single-atom chemical sensitivity. Additionally, the integration of artificial intelligence, machine learning, and big-data science is expected to significantly enhance the impact of STEM techniques on a wide range of research fields.