Approaching strain limit of two-dimensional MoS₂ via chalcogenide substitution

Strain engineering is a promising method for tuning the electronic properties of two-dimensional (2D) materials, which are capable of sustaining enormous strain thanks to their atomic thinness. However, applying a large and homogeneous strain on these 2D materials, including the typical semiconductor MoS₂, remains cumbersome. Here we report a facile strategy for the fabrication of highly strained MoS₂ via chalcogenide substitution reaction (CSR) of MoTe₂ with lattice inheritance. The MoS₂ resulting from the sulfurized MoTe₂ sustains ultra large in-plane strain (approaching its strength limit ~10%) with great homogeneity. Furthermore, the strain can be deterministically and continuously tuned to ~1.5% by simply varying the processing temperature. Thanks to the fine control of our CSR process, we demonstrate a heterostructure of strained MoS₂/MoTe₂ with abrupt interface. Finally, we verify that such a large strain potentially allows the modulation of MoS₂ bandgap over an ultra-broad range (~1 eV). Our controllable CSR strategy paves the way for the fabrication of highly strained 2D materials for applications in devices.