Strain mapping of three-dimensionally structured two-dimensional materials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41758957.
- Also identified by DOI 10.1126/sciadv.adz7908 and PMC identifier 12947876.
- Licence recorded as CC BY-NC.
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Abstract
Strain plays a crucial role in tuning materials' properties, influencing their optical, electrical, and chemical performances. In two-dimensional (2D) materials, applied stress often induces out-of-plane deformation, resulting in a more intricate three-dimensional (3D) topography, where mapping the strain remains a challenge due to the limitations of conventional characterization techniques. In this work, we introduce BRIGHT (Bragg-Rod Informed, Gradient-based Height-mapping Technique), an integrated method for reconstructing both the topography and planar strain profile of 3D-structured 2D materials using nanobeam four-dimensional scanning transmission electron microscopy (4D-STEM). We apply BRIGHT to a MoS<sub>2</sub>-MoSe<sub>2</sub> transition metal dichalcogenide (TMD) lateral heterojunctions exhibiting built-in strain and out-of-plane ripples and show that varying heterojunction widths lead to distinct surface morphologies and corresponding changes in the planar strain distribution. These results establish a foundation for more effective strain engineering in 2D materials by accounting for out-of-plane structural features, thereby enabling more precise control of strain-dependent properties.