Electron Beam Manipulation on the Moiré Superlattice of Bilayer WS 2

The moiré superlattice in twisted transition metal dichalcogenides (TMDCs) offers a versatile platform for exploring electronic properties and correlated quantum phenomena. However, conventional fabrication methods using transfer and stacking techniques suffer from interfacial contamination and limited scalability. Here, we introduce an in situ focused electron beam irradiation approach to dynamically manipulate and characterize the moiré superlattice in bilayer 2H-WS2 in TEM. We achieve real-time moiré pattern control, enabling precise twist angle adjustments (6-10°). Prolonged irradiation induces displacement of tungsten (W) and sulfur (S) atoms from the moiré superlattice, which migrate to heal vacancies in adjacent monolayers, ultimately collapsing the superlattice into a WS2 monolayer and revealing an unexpected atomic-scale self-repair mechanism. This technique advances the study of twistronics in 2D quantum materials by providing a pathway for atomically precise engineering of moiré-driven electronic states while highlighting the potential of electron beam lithography (EBL) for the controllable fabrication of moiré devices.