Figure 3.

Preparation approaches of 2D Bi₂Se₃ flakes

(A) Schematic diagram of solution synthesis of Bi₂Se₃ flakes.

(B) Morphology of the as-synthesized Bi₂Se₃ flakes.

(C) Selected area diffraction pattern of Bi₂Se₃ flakes. (B and C) Reproduced with permission from (Zhang et al., 2011). Copyright 2011 American Chemical Society.

(D) Schematic illustration of van der Waals epitaxial growth of Bi₂Se₃ flakes.

(E) Optical image of a triangular Bi₂Se₃ flake with a lateral size of 0.25 mm.

(F) High-magnification TEM image of the as-grown Bi₂Se₃ flake. (D–F) Reproduced with permission from (Wang et al., 2018). Copyright 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

(G) Schematic representation of procedures for patterning of 2D Bi₂Se₃ flakes.

(H) Representative optical image of large-scale Bi₂Se₃ array.

(I) Atomic force microtopography of a 2 × 2 Bi₂Se₃ array with a uniform thickness of 2 nm. (G-I) Reproduced with permission from (Zheng et al., 2015). Copyright 2015 Springer Nature.