sp^(2) to sp^(3) hybridization transformation in 2D metal-semiconductor contact interface suppresses tunneling barrier and Fermi level pinning simultaneously  

作　　者：Wenchao Shan Anqi Shi Zhuorong Zhong Xiuyun Zhang Bing Wang Yongtao Li Xianghong Niu 

机构地区：[1]School of Science, State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) and College of Electronic and Optical Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210023, China [2]College of Physics Science and Technology, Yangzhou University, Yangzhou, 225002, China [3]Institute for Computational Materials Science, Joint Center for Theoretical Physics (JCTP), School of Physics and Electronics, Henan University, Kaifeng, 475004, China [4]Key Laboratory of Quantum Materials and Devices (Southeast University), Ministry of Education, Nanjing, 211189, China

出　　处：《Nano Research》2024年第11期10227-10234,共8页纳米研究（英文版）

基　　金：supported by China Postdoctoral Science Foundation(No.2022M711691);the National Natural Science Foundation of China(Nos.12104130 and 12304085);Six talent peaks project in Jiangsu Province(No.XCL-104);the open research fund of Key Laboratory of Quantum Materials and Devices(Southeast University);Ministry of Education(No.3207022401C3);Natural Science Foundation of Nanjing University of Posts and Telecommunications(No.NY221102).

摘　　要：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 sp^(2) to sp^(3) 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 X_(3)C_(2) (X = Cd, Hg, and Zn) metal and the 2D MSi_(2)N_(4) (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 (P TB) is only 3.11%. As expected, the P TB can be significantly improved, as high as 48.73%, when MSi_(2)N_(4), accompanied by surface nitrogen vacancies, forms an interface covalent bond with X_(3)C_(2). Simultaneously, weak FLP and Ohmic contact remain at the covalent-bond-based surface, attributing to the protection of the MSi_(2)N_(4) 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.

关 键 词：two-dimensional(2D)material metal-semiconductor contacts tunneling-barrier Schottky barrier density functional theory 

分 类 号：TB31[一般工业技术—材料科学与工程]