In Situ TEM Study of Electrical Property and Mechanical Deformation in MoS/Graphene Heterostructures.

We present a versatile method for synthesizing high-quality molybdenum disulfide (MoS) crystals on graphite foil edges via chemical vapor deposition (CVD). This results in MoS/graphene heterostructures with precise epitaxial layers and no rotational misalignment, eliminating the need for transfer processes and reducing contamination. Utilizing in situ transmission electron microscopy (TEM) equipped with a nano-manipulator and tungsten probe, we mechanically induce the folding, wrinkling, and tearing of freestanding MoS crystals, enabling the real-time observation of structural changes at high temporal and spatial resolutions. By applying a bias voltage through the probe, we measure the electrical properties under mechanical stress, revealing near-ohmic behavior due to compatible work functions. This approach facilitates the real-time study of mechanical and electrical properties of MoS crystals and can be extended to other two-dimensional materials, thereby advancing applications in flexible and bendable electronics.