Localized exciton anatomy and band gap energy modulation in 1D MoS₂ nanostructures

This is a summary highlighting the application of EELSFitter in this publication. For more detail about the work presented, please refer to the publication itself [van der Lippe et al., 2023]

Abstract

This study presents an in-depth investigation of the electronic properties and bandgap energy distribution in 1D molybdenum disulfide (1D-MoS₂) nanostructures. Through a combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and electron energy-loss spectroscopy (EELS), it reveals significant differences between 1D-MoS₂ nanostructures and their 2D counterparts, shedding light on their localized exciton behavior and their bandgap energy modulation within the nanostructures. Excitonic peaks at around 2 and 3 eV appear localized at the ends or along the sides of the 1D-MoS₂nanostructures, while the plasmonic resonance at 8.3 eV retains its inner-region localization. It demonstrates the spatial dependence of the bandgap energy, with the central region exhibiting a bandgap of approximately 1.2 eV, consistent with bulk MoS₂, while regions characterized by curvature-induced local strain fields exhibit instead a noticeable reduction. The findings provide valuable insights into the intricate relationship between excitonic behavior and bandgap sensitivity in 1D-MoS₂ nanostructures, streamlining the design and optimization of nanophotonic and optoelectronic devices.

Fig. 10 Spatially-resolved band gap energy in 1D-MoS₂ nanostructures. The median value (second column) and 90% CL lower and upper bounds (first and third column, respectively) for the band gap energy \(E_{bg}\) determined across the 1D-MoS₂ nanostructures considered in Figs. 3 (top) and 4 (bottom).