Elasticity of MoS₂ sheets by mechanical deformation observed by in situ electron microscopy

MoS₂ has been the focus of extensive research due to its potential applications. More recently, the mechanical properties of MoS₂ layers have raised interest due to applications in flexible electronics. In this article, we show in situ transmission electron microcsopy (TEM) observation of the mechanical response of a few layers of MoS₂ to an external load. We used a scanning tunneling microscope (STM) tip mounted on a TEM stage to induce deformation on nanosheets of MoS₂ containing few layers. The results confirm the outstanding mechanical properties on the MoS₂. The layers can be bent close to 180°. However, when the tip is retrieved the initial structure is recovered. Evidence indicates that there is a significant bond reconstruction during the bending with an outstanding capability to recover the initial bond structure. The results show that flexibility of three layers of MoS₂ remains the same as a single layer while increasing the bending modulus by 3 orders of magnitude. Our findings are consistent with theoretical calculations and confirm the great potential of MoS₂ for applications.