Atomically Self-Healing of Structural Defects in Monolayer WSe2

Abstract

Minimizing disorder and defects is crucial for realizing the full potential of two-dimensional transition metal dichalcogenides (TMDs) materials and improving device performance to desired properties. However, the methods in defect control currently face challenges with overly large operational areas and lack of precision in targeting specific defects. Therefore, we propose a new method for the precise and universal defect healing of TMD materials, integrating real-time imaging with scanning transmission electron microscopy (STEM). This method employs electron beam irradiation to stimulate the diffusion migration of surface-adsorbed adatoms on TMD materials grown by low-temperature molecular beam epitaxy (MBE), and heal defects within the diffusion range. This approach covers defect repairs ranging from zero-dimensional vacancy defects to two-dimensional grain orientation alignment, demonstrating its universality in terms of the types of samples and defects. These findings offer insights into the use of atomic-level focused electron beams at appropriate voltages in STEM for defect healing, providing valuable experience for achieving atomic-level precise fabrication of TMD materials.