Nano Res. 14, 1390–1396 (2021)

Shallowing interfacial carrier trap in transition metal dichalcogenide heterostructures with interlayer hybridization

Xu Wu^1,2,§, Jingsi Qiao^3,§, Liwei Liu^1,§, Yan Shao² , Zhongliu Liu² , Linfei Li² , Zhili Zhu² , Cong Wang³ , Zhixin Hu⁴ , Wei Ji³ , Yeliang Wang^1,2,5 , and Hongjun Gao^2,5

1 School of Information and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing 100081, China

2 Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China

3 Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China

4 Center for Joint Quantum Studies and Department of Physics, Tianjin University, Tianjin 300350, China

5 CAS Center for Excellence in Topological Quantum Computation, Beijing 100049, China

Email: Yeliang Wang ( yeliang.wang@bit.edu.cn )  Email: Ji, Wei ( wji@ruc.edu.cn )

Abstract

With the unique properties, layered transition metal dichalcogenide (TMD) and its heterostructures exhibit great potential for applications in electronics. The electrical performance, e.g., contact barrier and resistance to electrodes, of TMD heterostructure devices can be significantly tailored by employing the functional layers, called interlayer engineering. At the interface between different TMD layers, the dangling-bond states normally exist and act as traps against charge carrier flow. In this study, we propose a technique to suppress such carrier trap that uses enhanced interlayer hybridization to saturate dangling-bond states, as demonstrated in a strongly interlayer-coupled monolayer-bilayer PtSe₂ heterostructure. The hybridization between the unsaturated states and the interlayer electronic states of PtSe₂ significantly reduces the depth of carrier traps at the interface, as corroborated by our scanning tunnelling spectroscopic measurements and density functional theory calculations. The suppressed interfacial trap demonstrates that interlayer saturation may offer an efficient way to relay the charge flow at the interface of TMD heterostructures. Thus, this technique provides an effective way for optimizing the interface contact, the crucial issue exists in two-dimensional electronic community.