Three-dimensional surface topography of graphene by divergent beam electron diffraction

Area of Science:

• Materials Science
• Crystallography
• Surface Science

Background:

• Limited scanning techniques offer nanometre resolution for surface topography.
• No current methods allow non-invasive 3D imaging of thin free-standing crystalline material surfaces.

Purpose of the Study:

• Introduce a novel technique for high-resolution surface topography imaging.
• Enable non-invasive visualization of 3D surface topography and strain in crystalline materials.

Main Methods:

• Developed and applied divergent beam electron diffraction (DBED).
• Utilized low-energy electrons (50-250 eV) for imaging.
• Analyzed intensity contrast in first-order diffraction spots.

Main Results:

• DBED directly images inhomogeneity in atomic positions within crystals.
• Intensity contrast in DBED patterns correlates linearly with electron wavelength.
• Detected 3D atomic displacements as small as 1 angstrom.
• Achieved non-scanning, single-shot imaging of surface topography and strain distribution.

Conclusions:

• DBED offers a breakthrough for nanometre-scale surface topography and strain analysis.
• The technique is suitable for thin, free-standing crystalline materials.
• DBED provides a non-invasive, high-resolution imaging solution.