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Tong T, Chen R, Ke Y, Wang Q, Wang X, Sun Q, Chen J, Gu Z, Yu Y, Wei H, Hao Y, Fan X, Zhang Q. Giant Second Harmonic Generation in Supertwisted WS 2 Spirals Grown in Step-Edge Particle-Induced Non-Euclidean Surfaces. ACS NANO 2024; 18:21939-21947. [PMID: 39115247 DOI: 10.1021/acsnano.4c02807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
In moiré crystals resulting from the stacking of twisted two-dimensional (2D) layered materials, a subtle adjustment in the twist angle surprisingly gives rise to a wide range of correlated optical and electrical properties. Herein, we report the synthesis of supertwisted WS2 spirals and the observation of giant second harmonic generation (SHG) in these spirals. Supertwisted WS2 spirals featuring different twist angles are synthesized on a Euclidean or step-edge particle-induced non-Euclidean surface using carefully designed water-assisted chemical vapor deposition. We observed an oscillatory dependence of SHG intensity on layer number, attributed to atomically phase-matched nonlinear dipoles within layers of supertwisted spiral crystals where inversion symmetry is restored. Through an investigation into the twist angle evolution of SHG intensity, we discovered that the stacking model between layers plays a crucial role in determining the nonlinearity, and the SHG signals in supertwisted spirals exhibit enhancements by a factor of 2 to 136 when compared with the SHG of the single-layer structure. These findings provide helpful perspectives on the rational growth of 2D twisted structures and the implementation of twist angle adjustable endowing them great potential for exploring strong coupling correlation physics and applications in the field of twistronics.
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Affiliation(s)
- Tong Tong
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, China
| | - Ruijie Chen
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Yuxuan Ke
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Qian Wang
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Xinchao Wang
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Qinjun Sun
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, China
| | - Jie Chen
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Zhiyuan Gu
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Ying Yu
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Hongyan Wei
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Yuying Hao
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Xiaopeng Fan
- College of Electronic Information and Optical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Qing Zhang
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
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Chen J, Yue X, Shan Y, Wang H, Han J, Wang H, Sheng C, Hu L, Liu R, Yang W, Qiu ZJ, Cong C. Twist-angle-dependent momentum-space direct and indirect interlayer excitons in WSe 2/WS 2 heterostructure. RSC Adv 2023; 13:18099-18107. [PMID: 37323440 PMCID: PMC10267672 DOI: 10.1039/d3ra02952b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 05/29/2023] [Indexed: 06/17/2023] Open
Abstract
Interlayer excitons (ILEs) in the van der Waals (vdW) heterostructures of type-II band alignment transition metal dichalcogenides (TMDCs) have attracted significant interest owing to their unique exciton properties and potential in quantum information applications. However, the new dimension that emerges with the stacking of structures with a twist angle leads to a more complex fine structure of ILEs, presenting both an opportunity and a challenge for the regulation of the interlayer excitons. In this study, we report the evolution of interlayer excitons with the twist angle in the WSe2/WS2 heterostructure and identify the direct (indirect) interlayer excitons by combining photoluminescence (PL) and density functional theory (DFT) calculations. Two interlayer excitons with opposite circular polarization assigned to the different transition paths of K-K and Q-K were observed. The nature of the direct (indirect) interlayer exciton was confirmed by circular polarization PL measurement, excitation power-dependent PL measurement and DFT calculations. Furthermore, by applying an external electric field to regulate the band structure of the WSe2/WS2 heterostructure and control the transition path of the interlayer excitons, we could successfully realize the regulation of interlayer exciton emission. This study provides more evidence for the twist-angle-based control of heterostructure properties.
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Affiliation(s)
- Jiajun Chen
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Xiaofei Yue
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Yabing Shan
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Huishan Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences Changning Road 865 Shanghai 200050 China
| | - Jinkun Han
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Haomin Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences Changning Road 865 Shanghai 200050 China
| | - Chenxu Sheng
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Laigui Hu
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Ran Liu
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Weihuang Yang
- Engineering Research Center of Smart Microsensors and Microsystems, Ministry of Education, College of Electronics and Information, Hangzhou Dianzi University Hangzhou 310018 China
| | - Zhi-Jun Qiu
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Chunxiao Cong
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
- Yiwu Research Institute of Fudan University Chengbei Road Yiwu City 322000 Zhejiang China
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