Films*

The ability to control nanoscale electronic properties by introducing macroscopic strain is of critical importance for the implementation of 2D materials into flexible electronics and next generation strain engineering devices. In this work we use scanning tunneling microscopy and spectroscopy (STM/STS) to correlate the atomic-scale lattice deformation and local electronic properties with a systematic macroscopic bending of monolayer molybdenum disulfide (MoS₂) films, using a custom-built sample holder. Using this technique, we find a reduction of the quasiparticle band gap with increasing strain. In addition, nanoscale strain relaxation of van der Waals monolayer sheets has been investigated and resulted in 1D ripples and 2D wrinkles which alter the local strain fields as well as the local electronic density of states.