6.

(a) Sequential growth scheme for coplanar heteroepitaxy of 1T′/2H MoTe₂ polymorphs. (b) Representative SEM images of the first (left) and second (right) types of crystallographic variants in the heterostructures between 1T′- and 2H-MoTe₂ crystals. (c) Low-magnification TEM image of 1T′/2H-MoTe₂ and their SAED pattern (inset). (a–c) Reproduced with permission from ref . Copyright 2017 Spring Nature. (d) Optical image of the MoO _x pattern (left) and the MoTe₂ heterophase pattern after tellurizing the oxide pattern (right). (e) Raman mapping images of the heterophase pattern with 231 cm^–1 (E_2g mode of 2H MoTe₂, red) and 160 cm^–1 (A_g mode of 1T′ MoTe₂, blue) peak intensities. (f) Typical STEM image of an atomically straight boundary of 2H/1T′ MoTe₂. Inset: large-scale SEM image of the heterophase structures. (g) STEM images of 2H (left) and 1T′ (right) MoTe₂ near the boundary. (d–g) Reproduced with permission from ref . Copyright 2019 Spring Nature. (h) The schematic diagrams for the in-plane 2D epitaxy synthesis of wafer-scale single-crystalline 2H MoTe₂ thin film. (i) Optical image of a 2H MoTe₂ nanoflake assembled in the center of the 1T′ MoTe₂ wafer as a seed to induce the phase transition and recrystallization (top) and the wafer after intermediate growth at 650 °C for 2 h (bottom). Inset shows the seed crystal with a needle probe-punched hole. (j) The cross-sectional HAADF-STEM image and zoomed-in image of the seed region. (k) Electron backscattered diffraction (EBSD) characterization of the wafer-scale single crystalline MoTe₂. (h–k) Reproduced with permission from ref . Copyright 2021 The American Association for the Advancement of Science. (l) Schematic diagrams of the in-plane 2D epitaxy of single-crystal 2H-MoTe₂ on a 3D architecture. (m) Cross-sectional HAADF-STEM images at the interface of the 2H-MoTe₂ film and a fin architecture. (l,m) Reproduced with permission from ref . Copyright 2022 Spring Nature.