Effective Strain Engineering of 2D Materials via Metal Deposition

2D materials, especially their monolayers, have garnered significant attention due to their unique electrical, optical and mechanical properties. Strain engineering is an effective way to modulate these properties. However, challenges remain in preventing slip or decoupling between the 2D material and the substrate due to the inherent weak van der Waals interactions. In this study, metal films are employed to apply strain to 2D materials. The high surface energy of metals helps to provide higher interaction forces, thereby improving strain transfer efficiency. Biaxial compressive and uniaxial tensile strain can be applied to monolayer MoS₂, with the highest modulation rate of 542 and 161.7 meV/%, respectively, as characterized by photoluminescence (PL) spectra. Furthermore, this new approach can be broader to other 2D materials, such as WS₂ or WSe₂, allowing for precise control over strain manipulation. The work introduces a promising new approach for efficient and controllable strain engineering of 2D materials.