Complete Strain Mapping of Nanosheets of Transition Metal Chalcogenides

Holding promise for future electronics because of their unique band structures, quasi-two-dimensional (quasi-2D) materials host electronic and mechanical properties sensitive to crystal strains in all three dimensions. Quantifying the crystal strain is a prerequisite to correlating it with the performance of the relevant device, and calls for fast characterization methods compatible with the potential devices and applications. Here we bridge this knowledge gap using fly-scan nano X-ray diffraction with strain sensitivity below 0.001 over sub 100 µm length scales. Coherent diffraction patterns were collected from a thin sheet of 1T-TaS₂ using an area detector by scanning across and rotating the sample. Reconstructing from the resulting five-dimensional datasets yields information on the morphology of and the strain distribution around micron and sub-micron ‘bubbles’ which form spontaneously in the quasi-2D plane. Our studies thus open way to experimentally quantify local strains in these quasi-2D materials and will allow better understanding of strains in tuning material properties.