Using first-principles calculations, we study the structural and electronic properties of the bilayer SnS/graphene, bilayer SnS/bilayer graphene (AA-stacked), bilayer SnS/bilayer graphene (AB-stacked) and monolayer SnS/ graphene/monolayer SnS van der Waals (vdW) heterostructures. Electronic properties of all components of the vdW heterostructures are well preserved, which reflects the weakness of the vdW interaction. In the cases of bilayer SnS/graphene and bilayer SnS/bilayer graphene (AA-stacked), an Ohmic contact is formed which can be turned first into p-type and then into n-type Schottky contacts via application of external electric field. Calculations show that an Ohmic contact is also formed at the interface of bilayer SnS/bilayer graphene (AB-stacked) heterostructure, but interestingly, by applying the perpendicular electric field a transition from semimetal/semiconductor contact to semiconductor/semiconductor one occurs which can enhance its optical properties. Alternatively, in the monolayer SnS/graphene/monolayer SnS vdW heterostructure, a p-type Schottky contact is established that changes into Ohmic contact under an applied electric field. Our results clearly indicate that the electronic properties of the vdW heterostructures can be tuned efficiently by external electric field, which is important in designing of new nanoelectronic devices.

使用第一性原理计算，我们研究了双层 SnS/石墨烯、双层 SnS/双层石墨烯（AA 堆叠）、双层 SnS/双层石墨烯（AB 堆叠）和单层 SnS/石墨烯/单层 SnS van 的结构和电子特性der Waals (vdW) 异质结构。vdW 异质结构的所有组件的电子特性都得到很好的保留，这反映了 vdW 相互作用的弱点。在双层 SnS/石墨烯和双层 SnS/双层石墨烯（AA 堆叠）的情况下，形成欧姆接触，通过施加外部电场可以首先转变为 p 型，然后转变为 n 型肖特基接触。计算表明，在双层 SnS/双层石墨烯（AB 堆叠）异质结构的界面处也形成了欧姆接触，但有趣的是，通过施加垂直电场，会发生从半金属/半导体接触到半导体/半导体接触的转变，这可以增强其光学特性。或者，在单层 SnS/石墨烯/单层 SnS vdW 异质结构中，建立了 p 型肖特基接触，该接触在施加的电场下变为欧姆接触。我们的结果清楚地表明，vdW 异质结构的电子特性可以通过外部电场有效调节，这对于设计新型纳米电子器件非常重要。建立 p 型肖特基接触，在外加电场下转变为欧姆接触。我们的结果清楚地表明，vdW 异质结构的电子特性可以通过外部电场有效调节，这对于设计新型纳米电子器件非常重要。建立 p 型肖特基接触，在外加电场下转变为欧姆接触。我们的结果清楚地表明，vdW 异质结构的电子特性可以通过外部电场有效调节，这对于设计新型纳米电子器件非常重要。