Guo Hao, Lang Xiufeng, Tian Xiaobao, Jiang Wentao, Wang Guangzhao
School of Urban Construction, Hebei Normal University of Science & Technology, Qinhuangdao 066004, People's Republic of China.
Material Simulation and Computing Laboratory, Department of Physics, Hebei Normal University of Science & Technology, Qinghuangdao 066004, People's Republic of China.
Nanotechnology. 2022 Jul 28;33(42). doi: 10.1088/1361-6528/ac800d.
Two-dimensional (2D) Janus materials have attracted significant attention due to their asymmetrical structures and unique electronic properties. In this work, by using the first-principles calculation based on density functional theory, we systematically investigate the electronic properties of 6 types of Janus-GaGraphene van der Waals heterostructures (vdWHs). The results show that the Janus-GaGraphene vdWHs are connected by weak interlayer vdW forces and can form n-type Schottky contact, p-type Schottky contact or Ohmic contact when the spin-orbit coupling (SOC) is not considered. However, when considering SOC, only the SeGa2S/G and G/SeGa2S vdWHs show n-type Schottky contact, and other vdWHs show Ohmic contacts. In addition, the Schottky barriers and contact types of SeGaS/Graphene and Graphene/SeGaS vdWHs can be effectively modulated by interlayer distance and biaxial strain. They can be transformed from intrinsic n-type Schottky contact to p-type Schottky contact when the interlayer distances are smaller than 2.65 Å and 2.90 Å, respectively. They can also be transformed to Ohmic contact by applying external biaxial strain. Our work can provide useful guidelines for designing Schottky nanodiodes, field effect transistors or other low-resistance nanodevices based on the 2D vdWHs.
二维（2D）Janus材料因其不对称结构和独特的电子特性而备受关注。在这项工作中，我们基于密度泛函理论使用第一性原理计算，系统地研究了6种Janus-GaGraphene范德华异质结构（vdWHs）的电子特性。结果表明，Janus-GaGraphene vdWHs通过弱层间范德华力连接，在不考虑自旋轨道耦合（SOC）时可形成n型肖特基接触、p型肖特基接触或欧姆接触。然而，考虑SOC时，只有SeGa2S/G和G/SeGa2S vdWHs表现出n型肖特基接触，其他vdWHs表现出欧姆接触。此外，SeGaS/石墨烯和石墨烯/SeGaS vdWHs的肖特基势垒和接触类型可通过层间距离和双轴应变有效调制。当层间距离分别小于2.65 Å和2.90 Å时，它们可从本征n型肖特基接触转变为p型肖特基接触。通过施加外部双轴应变，它们也可转变为欧姆接触。我们的工作可为基于二维vdWHs设计肖特基纳米二极管、场效应晶体管或其他低电阻纳米器件提供有用的指导。
