@article{Shan2024, 
author = {Wenchao Shan and Anqi Shi and Zhuorong Zhong and Xiuyun Zhang and Bing Wang and Yongtao Li and Xianghong Niu},
title = {sp2 to sp3 hybridization transformation in 2D metal-semiconductor contact interface suppresses tunneling barrier and Fermi level pinning simultaneously},
year = {2024},
journal = {Nano Research},
volume = {17},
number = {11},
pages = {10227-10234},
keywords = {two-dimensional (2D) material, metal-semiconductor contacts, tunneling-barrier, Schottky barrier, density functional theory},
url = {https://www.sciopen.com/article/10.1007/s12274-024-6877-x},
doi = {10.1007/s12274-024-6877-x},
abstract = {Van der Waals (vdWs) stacking of two-dimensional (2D) materials can effectively weaken the Fermi level pinning (FLP) effect in metal/semiconductor contacts due to dangling-bond-free surfaces. However, the inherent vdWs gap always induces a considerable tunneling barrier, significantly limiting carrier injection. Herein, by inducing a sp2 to sp3 hybridization transformation in 2D carbon-based metal via surface defect engineering, the large orbital overlap can form an efficient carrier channel, overcoming the tunneling barrier. Specifically, by selecting the 2D carbon-based X3C2 (X = Cd, Hg, and Zn) metal and the 2D MSi2N4 (M = Cr, Hf, Mo, Ti, V, and Zr) semiconductor, we constructed 36 metal/semiconductor contacts. For vdWs contacts, although Ohmic contacts can be formed at the interface, the highest tunneling probability (PTB) is only 3.11%. As expected, the PTB can be significantly improved, as high as 48.73%, when MSi2N4, accompanied by surface nitrogen vacancies, forms an interface covalent bond with X3C2. Simultaneously, weak FLP and Ohmic contact remain at the covalent-bond-based surface, attributing to the protection of the MSi2N4 band-edge electronic states by the outlying Si-N sublayer. Our work provides a promising path for advancing the progress of 2D electronic and photoelectronic devices.}
}