Chromatic Aberration Correction for Atomic Resolution TEM Imaging from 20 to 80 kV

Area of Science:

• Materials Science
• Physics
• Electron Microscopy

Background:

• Atomic resolution in Transmission Electron Microscopy (TEM) is crucial for studying thin and light-atom materials.
• Low beam energies are required to minimize knock-on damage, but this exacerbates chromatic aberration, degrading image resolution.
• Existing TEMs struggle to balance low-voltage operation for damage reduction with high-resolution imaging.

Purpose of the Study:

• To introduce a novel aberration corrector for TEM capable of simultaneously correcting chromatic (Cc) and spherical (Cs) aberrations.
• To enable high-resolution, phase-contrast imaging of light-atom materials at reduced accelerating voltages (20-80 kV).
• To overcome the resolution limitations imposed by chromatic aberration at low beam energies.

Main Methods:

• Development and implementation of a new C_{c}/C_{s} corrector within the SALVE project framework.
• Correction of axial aberrations up to fifth order and dominant off-axial aberrations.
• Optimization of phase-contrast imaging conditions for weak signals from light atoms using a large optical aperture (≥ 55 mrad).

Main Results:

• The new corrector effectively corrects both chromatic and spherical aberrations across a voltage range of 20-80 kV.
• Information transfer is no longer limited by chromatic aberrations within the specified aperture.
• Demonstrated unprecedented contrast and resolution in 30 kV phase-contrast TEM images of graphene and molybdenum disulfide, matching theoretical calculations.

Conclusions:

• The developed aberration corrector significantly enhances TEM capabilities for light-atom materials.
• Atomic resolution imaging is achievable at lower, damage-minimizing beam energies.
• This technology opens new avenues for high-resolution characterization of sensitive materials in electron microscopy.