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Thermomechanical Nanostraining of Two-Dimensional Materials
Xia Liu1, Amit Kumar Sachan2, Samuel Tobias Howell1
1Microsystems Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
Nano Letters
|October 8, 2020
Summary
Researchers developed a thermomechanical nanoindentation technique to precisely control nanoscale strain patterns in 2D materials. This method allows for tunable bandgap modulation in materials like molybdenum disulfide (MoS2) for advanced electronic devices.
Area of Science:
- Materials Science
- Nanotechnology
- Condensed Matter Physics
Background:
- Local bandgap tuning in 2D materials is crucial for electronic and optoelectronic devices.
- Controllable nanoscale strain engineering in 2D materials remains a significant challenge.
Purpose of the Study:
- To develop a method for creating arbitrary strain nanopatterns in 2D materials.
- To achieve localized bandgap modulation with high spatial resolution.
Main Methods:
- Thermomechanical nanoindentation using a scanning probe.
- Utilizing van der Waals interactions between 2D materials and a polymer layer.
- Inducing deformation via heat and indentation force from a heated probe.
Main Results:
- Demonstrated strain nanopatterning in 2D transition metal dichalcogenides and graphene.
- Achieved spatial resolution down to 20 nm.
- Spatially modulated the local bandgap of molybdenum disulfide (MoS2) up to 10% (180 meV).
- Determined a linear tuning rate of approximately -70 meV per percent of strain.
Conclusions:
- Thermomechanical nanoindentation offers a versatile tool for localized strain engineering of 2D materials.
- The technique enables precise control over bandgap modulation at the nanoscale.
- Facilitates investigation of strain effects in 2D materials with nanometer-scale resolution.
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