Tuning of Interlayer Interaction in MoS₂–WS₂ van der Waals Heterostructures Using Hydrostatic Pressure

Van der Waals heterostructures have recently attracted great interest of the scientific community due to their rich exotic physical properties and extensive application prospects. Therefore, we conducted pressure-dependent Raman and photoluminescence spectroscopic studies on MoS2–WS2 heterostructures in different twist angles (24.5 and 54°). Thus, it was confirmed that as the interlayer interaction increases under pressure, an electronic phase transition and a structural phase transition due to layer sliding are observed at ∼1.8 and ∼3.8 GPa in the HS-24.5° structures, while no phase transition is observed in the HS-54° structures. As a result of a larger tunable interlayer space in HS-24.5° structures, optical properties of HS-24.5° structures are more pressure-sensitive than those of the HS-54° structure. It is expected that this work will help comprehensively establish the correlation between the interlayer interactions and optical properties of vdW HSs at the atomic level. Understanding this correlation is crucial for the development of new excitonic devices.