Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People's Republic of China.
Nanotechnology. 2023 Apr 26;34(28). doi: 10.1088/1361-6528/acc9cb.
Van der Waals materials and their interfaces play critical roles in defining electrical contacts for nanoelectronics and developing vehicles for mechanoelectrical energy conversion. In this work, we propose a vertical strain engineering approach by enforcing pressure across the heterostructures. First-principles calculations show that the in-plane band structures of 2D materials such as graphene, h-BN, and MoSas well as the electronic coupling at their contacts can be significantly modified. For the graphene/h-BN contact, a band gap in graphene is opened, while at the graphene/MoSinterface, the band gap of MoSand the Schottky barrier height at contact diminish. Changes and transitions in the nature of contacts are attributed to localized orbital coupling and analyzed through the redistribution of charge densities, the crystal orbital Hamilton population, and electron localization, which yield consistent measures. These findings offer key insights into the understanding of interfacial interaction between 2D materials as well as the efficiency of electronic transport and energy conversion processes.
范德华材料及其界面在定义纳米电子学的电接触和开发机电能量转换载体方面起着关键作用。在这项工作中，我们通过在异质结构上施加压力来提出一种垂直应变工程方法。第一性原理计算表明，二维材料（如石墨烯、h-BN 和 MoS 等）的面内能带结构以及它们接触处的电子耦合可以得到显著修饰。对于石墨烯/h-BN 接触，石墨烯中的带隙被打开，而在石墨烯/MoS 界面，MoS 的带隙和接触处的肖特基势垒高度减小。接触性质的变化和转变归因于局域轨道耦合，并通过电荷密度的重新分布、晶体轨道哈密顿人口和电子定位进行分析，得出一致的度量。这些发现为理解二维材料之间的界面相互作用以及电子输运和能量转换过程的效率提供了关键见解。
