Abstract
The outstanding properties of transition metal dichalcogenide (TMD) monolayers and their van der Waals (vdW) heterostructures, arising from their structure and the modified electron-hole Coulomb interaction in 2D, make them promising candidates for potential electro-optical devices. However, the production of reproducible devices remains challenging, partly due to variability at the nanometer to atomic scales. Thus, access to chemical, structural, and optical characterization at these length scales is essential. While electron microscopy and spectroscopy can provide chemical and structural data, accessing the optical response at the nanoscale through electron spectroscopies has been hindered until recently. This review focuses on the application of two electron spectroscopies in scanning (transmission) electron microscopes, namely cathodoluminescence and electron energy-loss spectroscopy, to study the nano-optics of TMD atomic layers and their vdW heterostructures. How technological advancements can improve these spectroscopies, many of which are already underway, that will make them ideal for studying the physics of vdW heterostructures at the nanoscale will also be discussed.
| Original language | English |
|---|---|
| Article number | 012001 |
| Journal | 2D Materials |
| Volume | 12 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2025 |
Funding
This work was supported by the Center for Nanophase Materials Sciences (CNMS), which is a U.S. Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. The authors acknowledge funding from the ANR JCJC Grant SpinE (Reference No. ANR-20-CE42-0020), and funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 101017720 (EBEAM).
Keywords
- SEM
- STEM
- cathodoluminescence
- electron energy-loss spectroscopy
- electron spectroscopy
- nano-optics