Tang Yingqi, Li Hao, Mao Xiaotong, Xie Ju, Lee Jin Yong, Fu Aiping
College of Chemistry and Chemical Engineering, State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University Qingdao 266071 China
Department of Chemistry, Sungkyunkwan University Suwon 16419 Korea
RSC Adv. 2019 Oct 29;9(60):34986-34994. doi: 10.1039/c9ra05692k. eCollection 2019 Oct 28.
First-principles calculations have been performed to explore the structural and electronic properties of bidirectional heterostructures composed of graphene and (MoS) /(WS) ( = 1, 2, 3) lateral composites and compare them with those of heterobilayers formed by graphene and pristine MS (M = Mo, W). The band gaps of the lateral heterostructures lie between those of pristine MoS and WS. The weak coupling between the two layers can induce a tiny band-gap opening of graphene and formation of an n-type Schottky contact at the G-(MoS) /(WS) interface. Moreover, the combination ratio of MoS/WS can control the electronic properties of G-(MoS) /(WS) . By applying external electric fields, the band gaps of (MoS) /(WS) ( = 0, 1, 2, 3, 4) monolayers undergo a direct-indirect transition, and semiconductor-metal transitions can be found in WS. External electric fields can also be used effectively to tune the binding energies, charge transfers, and band structures (the types of Schottky and Ohmic contacts) of G-(MoS) /(WS) heterostructures. These findings suggest that G-(MoS) /(WS) heterostructures can serve as high-performance nano-electronic devices.
已进行第一性原理计算，以探索由石墨烯与(MoS) /(WS) ( = 1, 2, 3)横向复合材料组成的双向异质结构的结构和电子特性，并将其与由石墨烯和原始MS(M = Mo, W)形成的异质双层的结构和电子特性进行比较。横向异质结构的带隙介于原始MoS和WS的带隙之间。两层之间的弱耦合可诱导石墨烯产生微小的带隙开口，并在G-(MoS) /(WS)界面处形成n型肖特基接触。此外，MoS/WS的组合比例可控制G-(MoS) /(WS)的电子特性。通过施加外部电场，(MoS) /(WS) ( = 0, 1, 2, 3, 4)单层的带隙会发生直接-间接跃迁，并且在WS中可发现半导体-金属跃迁。外部电场还可有效地用于调节G-(MoS) /(WS)异质结构的结合能、电荷转移和能带结构（肖特基和欧姆接触的类型）。这些发现表明，G-(MoS) /(WS)异质结构可作为高性能纳米电子器件。
