Synthesis of Low-Symmetry 2D Transition Metal Dichalcogenides by Chemical Vapor Deposition

Low-symmetry two-dimensional materials are a new type of nanomaterials with few lattice symmetry operations and only atomic-level thickness in the longitudinal direction. In the two-dimensional transition metal dichalcogenides (TMDs) system, 1T'-MoTe2, 1T'-WTe2, 1T'-ReS2 and 1T'-ReSe2 are typical low-symmetry members. The unique lattice symmetry brings them rich anisotropic physical and chemical properties, so they have special application prospects in the fields of micro-nano photonics, tactile sensors, and anisotropic logic devices. The basic research and application development of low-symmetry two-dimensional TMD materials relies on the high-quality, large-size, and stable preparation of such materials. Therefore, this paper takes these four types of materials as typical materials, first classifies them according to metal precursors, and reviews the chemical vapor deposition (CVD) preparation methods of low-symmetry two-dimensional TMD materials in recent years. According to the characteristics of 1T '-MoTe2 easy to undergo phase transition and weak interaction between 1T'-ReS2, 1T'-ReSe2 and the substrate during the preparation process, the phase regulation mechanism in the preparation process of 1T'-MoTe2 and the substrate engineering research in the preparation process of 1T'-ReS(2)and 1T'-ReSe2 were introduced. Finally, this paper looks forward to the future challenges and opportunities of low-symmetry 2D TMDs materials.