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Nano Research

Article Title

Quasi-freestanding, striped WS2 monolayer with an invariable band gap on Au(001)

Authors

Min Hong, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Xiebo Zhou, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Jianping Shi, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Yue Qi, Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Zhepeng Zhang, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Qiyi Fang, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Yaguang Guo, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
Yajuan Sun, State Key Laboratory of Coal-based Low-carbon Energy, ENN Group Co., Ltd., Langfang 065001, China
Zhongfan Liu, Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
Yuanchang Li, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
Qian Wang, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China Center for Applied Physics and Technology, Peking University, Beijing 100871, China
Yanfeng Zhang, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China

Keywords

WS2, Au (001), striped superstructure, interfacial interaction, STM/STS

Abstract

ABSTRACT Revealing the structural/electronic features and interfacial interactions of monolayer MoS2 and WS2 on metals is essential to evaluating the performance of related devices. In this study, we focused on the atomic-scale features of monolayer WS2 on Au(001) synthesized via chemical vapor deposition. Scanning tunneling microscopy and spectroscopy reveal that the WS2/Au(001) system exhibits a striped superstructure similar to that of MoS2/Au(001) but weaker interfacial interactions, as evidenced by experimental and theoretical investigations. Specifically, the WS2/Au(001) band gap exhibits a relatively intrinsic value of ~2.0 eV. However, the band gap can gradually decrease to ~1.5 eV when the sample annealing temperature increases from ~370 to 720 °C. In addition, the doping level (or Fermi energy) of monolayer WS2/Au(001) varies little over the valley and ridge regions of the striped patterns because of the homogenous distributions of point defects introduced by annealing. Briefly, this work provides an in-depth investigation into the interfacial interactions and electronic properties of monolayer MX2 on metal substrates.

Graphical Abstract

Publisher

Tsinghua University Press

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