Liu Dexing, Liu Ziyi, Zhu Jiahao, Zhang Min
School of Electronic and Computer Engineering, Peking University, Shenzhen 518055, China.
Mater Horiz. 2023 Nov 27;10(12):5621-5632. doi: 10.1039/d3mh00736g.
Achieving efficient electrical contacts in two-dimensional (2D) semiconductors is increasingly critical with the continuous scaling down of transistors. van der Waals (vdW) contacts with weak Fermi-level pinning are still hindered by the additional contact resistance due to weak interlayer coupling. Here, based on first-principles, we propose to exploit hydrogen-bonding interactions to intrinsically overcome the inherent vdW gap. Various metal/semiconductor heterojunctions with hydroxyl-terminated MXenes as the metal electrode demonstrate clean Ohmic contacts with ultralow contact resistance approaching the quantum limit strong hydrogen-bonding of O-H⋯X (X = N, O, S, Se, ) at the interface. Hydrogen-bonding contacts are further shown to be an advantageous approach to achieve near-perfect N-type contacts for emerging 2D nitride, oxide, halide, and chalcogenide semiconductors that can simultaneously approach the modified Schottky-Mott limit. We finally discuss the general design concepts for hydrogen-bonding contacts, demonstrating their potential to go beyond vdW contacts in achieving ideal electrical contacts in 2D semiconductors.
随着晶体管不断缩小，在二维（2D）半导体中实现高效电接触变得越来越关键。具有弱费米能级钉扎的范德华（vdW）接触仍然受到层间耦合较弱导致的额外接触电阻的阻碍。在此，基于第一性原理，我们提出利用氢键相互作用从本质上克服固有的vdW能隙。以羟基封端的MXenes作为金属电极的各种金属/半导体异质结表现出清洁的欧姆接触，其超低接触电阻接近量子极限，这归因于界面处O-H⋯X（X = N、O、S、Se等）的强氢键作用。氢键接触进一步被证明是一种有利的方法，可用于为新兴的二维氮化物、氧化物、卤化物和硫族化物半导体实现接近完美的N型接触，这些半导体能够同时接近修正的肖特基-莫特极限。我们最后讨论了氢键接触的一般设计概念，展示了它们在二维半导体中实现理想电接触方面超越vdW接触的潜力。
