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. (c) 2021 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.