Strain effects in MoS2 monolayer: a scanning probe microscopy study

Two-dimensional (2D) transition metal dichalcogenides (TMDs), such as molybdenum disulphide (MoS2), are a class of materials with emerging and promising properties. Akin to graphene, individual atomic sheets of TMDs are capable of sustaining much larger mechanical strains compared to conventional semiconductors. Concomitantly, mechanical strain can strongly perturb the 2D material’s band structure, establishing a strong interplay between mechanical deformations and electronic and photonic properties. Here, we use diverse scanning probe microscopy techniques, ranging from atomic force nanoindentation to electrostatic force microscopy, to investigate H2-filled, biaxially strained, MoS2 monolayer membranes. On one side, we demonstrate that these latter can encapsulate H2 up to 10 MPa and can withstand exceptionally high deformations to an external loading. On the other, we investigate, via quantum capacitance measurements at the nanoscale, the effect of strain on the material band structure and on its local charge carrier distribution.