2023, Unveiling Strain-Enhanced Moiré Exciton Localization in twisted van der Waals Homostructures, Nano Research

2023, Unveiling Strain-Enhanced Moiré Exciton Localization in twisted van der Waals Homostructures, Nano Research

Abstract:

Moiré superlattices, arising from the controlled twisting of van der Waals homostructures at specific angles, have emerged as a promising platform for quantum emission applications.  Concurrently, the manipulation of strain provides a versatile strategy to finely adjust electronic band structures, enhance exciton luminescence efficiency, and establish a robust foundation for two-dimensional quantum light sources. However, the intricate interplay between strain and moiré potential remains partially unexplored. Here, we introduce a meticulously designed fusion of strain engineering and the twisted 2L-WSe₂/2L-WSe₂ homobilayers, resulting in the precise localization of moiré excitons. Employing low-temperature photoluminescence spectroscopy, we unveil the emergence of highly localized moiré-enhanced emission, characterized by the presence of multiple distinct emission lines. Furthermore, our investigation demonstrates the effective regulation of moiré potential depths through strain engineering, with the potential depths of strained and unstrained regions differing by 91%. By combining both experimental and theoretical approaches, our study elucidates the complex relationship between strain and moiré potential, thereby opening avenues for generating strain-induced moiré exciton single-photon sources.

Keywords: Moiré superlattices, strain engineering, moiré excitons, moiré potential

Link: https://link.springer.com/article/10.1007/s12274-023-6205-x

Unveiling strain-enhanced moiré exciton localization in twisted van der Waals homostructures.pdf