Rapid and Nondestructive Identification of Polytypism and Stacking Sequences in Few-Layer Molybdenum Diselenide by Raman Spectroscopy.

Various combinations of interlayer shear modes emerge in few-layer molybdenum diselenide grown by chemical vapor deposition depending on the stacking configuration of the sample. Raman measurements may also reveal polytypism and stacking faults, as supported by first principles calculations and high-resolution transmission electron microscopy. Thus, Raman spectroscopy is an important tool in probing stacking-dependent properties in few-layer 2D materials.