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Nano Research

Article Title

Controllable defects implantation in MoS2 grown by chemical vapor deposition for photoluminescence enhancement

Authors

Ke Wu, School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China
Zhe Li, School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
Jibo Tang, The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, China
Xianglong Lv, School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China Flexible Electronics Research Center, Huazhong University of Science and Technology, Wuhan, 430074, China
Hailing Wang, School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China Flexible Electronics Research Center, Huazhong University of Science and Technology, Wuhan, 430074, China
Ruichun Luo, Department of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai, 200240, China
Pan Liu, Department of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai, 200240, China
Lihua Qian, School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China Flexible Electronics Research Center, Huazhong University of Science and Technology, Wuhan, 430074, China
Shunping Zhang, School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China
Songliu Yuan, School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China

Keywords

CVD MoS2, hydrogen, sulfur vacancy, defect-bounded exciton, photoluminescence enhancement, Raman shifts

Abstract

ABSTRACT Photoluminescence (PL) of transition metal dichalcogenides (TMDs) can be engineered by controlling the density of defects, which provide active sites for electron-hole recombination, either radiatively or non-radiatively. However, the implantation of defects by external stimulation, such as uniaxial tension and irradiation, tends to introduce local damages or structural non-homogeneity, which greatly degrades their luminescence properties and impede their applicability in constructing optoelectronic devices. In this paper, we present a strategy to introduce a controllable level of defects into the MoS2 monolayers by adding a hydrogen flow during the chemical vapor deposition, without sacrificing their luminescence characteristics. The density of the defect is controlled directly by the concentration of hydrogen. For an appropriate hydrogen flux, the monolayer MoS2 sheets have three times stronger PL emission at the excitonic transitions, compared with those samples with nearly perfect crystalline structure. The defect-bounded exciton transitions at lower energies arising in the defective samples and are maximized when the total PL is the strongest. However, the B exciton, exhibits a monotonic decline as the defect density increases. The Raman spectra of the defective MoS2 reveal a redshift (blueshift) of the in-plane (out-of-plane) vibration modes as the hydrogen flux increases. All the evidence indicates that the generated defects are in the form of sulfur vacancies. This study renders the high-throughput synthesis of defective MoS2 possible for catalysis or light emitting applications.

Graphical Abstract

Publisher

Tsinghua University Press

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