Wong Lok-Wing, Huang Lingli, Zheng Fangyuan, Thi Quoc Huy, Zhao Jiong, Deng Qingming, Ly Thuc Hue
Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
Polytechnic University of Hong Kong Shenzhen Research Institute, Shenzhen, China.
Nat Commun. 2020 Aug 7;11(1):3982. doi: 10.1038/s41467-020-17784-3.
Electrical contact is an essential issue for all devices. Although the contacts of the emergent two-dimensional materials have been extensively investigated, it is still challenging to produce excellent contacts. The face and edge type contacts have been applied previously, however a comparative study on the site-specific contact performances is lacking. Here we report an in situ transmission electron microscopy study on the contact properties with a series of 2D materials. By manipulating the contact configurations in real time, it is confirmed that, for 2D semiconductors the vdW type face contacts exhibit superior conductivity compared with the non-vdW type contacts. The direct quantum tunneling across the vdW bonded interfaces are virtually more favorable than the Fowler-Nordheim tunneling across chemically bonded interfaces for contacts. Meanwhile, remarkable area, thickness, geometry, and defect site dependences are revealed. Our work sheds light on the significance of contact engineering for 2D materials in future applications.
电接触对于所有器件来说都是一个至关重要的问题。尽管新兴二维材料的接触已经得到了广泛研究，但要实现优异的接触仍然具有挑战性。此前已经应用了面接触和边缘接触类型，然而缺乏针对特定位置接触性能的比较研究。在此，我们报告了一项对一系列二维材料接触特性的原位透射电子显微镜研究。通过实时操控接触构型，证实了对于二维半导体，范德华（vdW）型面接触与非范德华型接触相比表现出卓越的导电性。对于接触而言，穿过范德华键合界面的直接量子隧穿实际上比穿过化学键合界面的福勒 - 诺德海姆隧穿更有利。同时，还揭示了显著的面积、厚度、几何形状和缺陷位置依赖性。我们的工作为二维材料在未来应用中的接触工程的重要性提供了启示。
