Perspectives of Two-dimensional Transition Metal DichalcogenideMonolayers

[摘要] The discovery of graphene, a novel two-dimensional (2D) nanostructure, has triggered an extensive study on monolayersfor diverse applications in Nano devices, optoelectronics, sensors, catalysts, and energy storage because of the easy fabrication,exceptional charge transport, thermal, optical, chemical, and mechanical properties [1]. As one of important members of 2Dmonolayers, 2D transition metal dichalcogenides (TMDs) monolayers show a wide range of electronic, optical, mechanical,chemical, and thermal properties [2]. TMDs have a chemical formula of MX2, where M is a transition metal element from group IV,group V, or group VI, and X is a chalcogen (S, Se, or Te). They are layered materials with weakly van der Walls interaction holdingtogether. Each layer is a sandwich structure (X–M–X), where a M-atom layer is enclosed within two X layers and the atoms inlayers are hexagonally packed [3]. Depending to stacking orders and metal atom coordination, the overall symmetry of TMD can behexagonal or rhombohedral, and the metal atoms have octahedral or trigonal prismatic coordination.