fig5

Figure 5. Vertical lattice mismatch-induced strain for 2D materials. (A) Experimental schematic diagram of TERS for Raman shift detection; (B) Spectral of 1D TERS measurements; (C) Tip-enhanced Raman spectroscopy was performed at the colored spots marked in the inset STM image; (A-C): quoted with permission from Li et al.^[41]; (D) STM image of a transverse heterojunction of WSe₂-MoS₂; (E) An instance of the moiré pattern observed in a strain-free MoS₂/WSe₂ bilayer stack; (F) A close-up image of the moiré pattern in (D) shows spatially varying strains; (D-F): quoted with permission from Zhang et al.^[79]; (G) Schematic diagram of the 2D multilayered VOPO₄-graphene heterostructure; (H-I) Distribution from 100 individual scans of VOPO₄-graphene heterostructures, showing the Raman shift of O-P-O and V=O (color orange indicates VOPO₄ nanoflakes, color green indicates VOPO₄-graphene, color blue indicates VOPO₄·2H₂O); (G-I): quoted with permission from Xiong et al.^[80]. STM: Scanning tunneling microscopy; TERS: tip-enhanced Raman spectroscopy; 2D: two-dimensional.