Unraveling weak interfacial coupling in NaCl/WSe2 heterostructures
Abstract
Resolving and controlling interfacial coupling between transition metal dichalcogenides and dielectric layer in heterostructures are of great importance in various physical phenomena. Here, we established the monolayer sodium chloride (NaCl) epitaxially grown on the monolayer tungsten selenide (WSe2) underlayer and demonstrated weak covalent-like quasi-bonding in the heterostructure. By using scanning tunneling microscopy, we observed the template effect of WSe2 lattices on NaCl epitaxy, with the edge of NaCl islands extending along three highly symmetric orientations of WSe2. NaCl islands also exhibited lower apparent height compared to WSe2 monolayers at various biases, which could be attributed to the almost unaffected electrostatic screening of NaCl within the weak interfacial coupling regime. Thermal stability experiments showed that the coupling strength of the NaCl/WSe2 interface is stronger than that of NaCl on Au(111) due to the extra quasi-bonding. Density functional theory calculations further verified the experimental observations and unveiled that the fundamental nature of interfacial coupling could arise from weak covalent-like quasi-bonding between Na+ ions and Se atoms accompanied by electron accumulation.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (9)
Peng-Cheng Pan
Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University , Changsha 410082,
Sheng-Yi Xie
Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University , Changsha 410082,
Yanlin Tao
Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University 1 , Changsha 410082,
Yulong Zeng
Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University , Changsha 410082,
Yuan Tian
Long-Jing Yin
Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University 1 , Changsha 410082,
Lijie Zhang
Li Zhang
Zhihui Qin