The introduction of the interlayer torsion angle of two-dimensional transition metal chalcogenides (TMDCs) provides a new idea for the performance control of TMDCs. The preparation of large-area, high-quality, full-torsion angle double-layer twisted angle TMDCs (TB-TMDCs) is the prerequisite for their large-scale application. However, due to the high energy barrier to be overcome, it is difficult to effectively prepare TB-TMDCs with large area, high quality and full torsion angle by chemical vapor deposition (CVD), which seriously limits its further development and application in the field of torsional electronics.
Recently, the research group of Professor Wang Xuewen from the team of Academician Huang Wei of Northwestern Polytechnical University, the research group of Professor Gan Xuetao of the School of Physical Science and Technology, and Professor Liu Zheng of Nanyang Technological University in Singapore, further proposed the introduction of inclined substrates to prepare TB-TMDCs in CVD systems on the basis of the previous proposal of reconstitution strategy to prepare TB-TMDCs (Nature Communications, 2024, 15, 562). The interlayer torsion angle of TB-WS2 is prepared from 0° to 120°, and the tunability of the second harmonic (SHG) with the interlayer torsion angle is observed, which provides a new method and idea for the design and optimization of two-dimensional semiconductor optoelectronic devices. The results were published in the journal Advanced Materials and selected as a Frontispiece paper. Associate Professor Xu Manzhang and Master Student Ji Hongjia of the Institute of Flexible Electronics and Ph.D. student Zhang Mingwen from the School of Physical Science and Technology are the co-first authors of this paper, and Academician Huang Wei, Professor Wang Xuewen and Professor Gan Xuetao are the co-corresponding authors.
The research team found that in the CVD system, the SiO2/Si substrate in the confined space was placed obliquely to change the reaction concentration gradient on the substrate surface, which promoted the torsional nucleation growth of TB-WS2, and prepared TB-WS2 with a full torsion angle range (0-120°), which provides a new idea for the direct in-situ growth of TB-TMDCs with high crystalline quality. The synergistic control of SHG signal intensity and phase in the TB-WS2 system is realized by the torsion angle, and the angle-dependent optical characteristics further confirm the potential application of TB-TMDCs in tunable optoelectronic devices, which provides a basis for the application of TB-TMDCs in the field of optoelectronic devices.
The above work has been supported by the National Key R&D Program of China, the National Natural Science Foundation of China Basic Science Center Project, general projects, youth projects, and basic scientific research funds for the Central Universities. Professor Wang Xuewen's research group has carried out research on special flexible electronic materials and intelligent sensing technology, and has been published in Nat. Commun. (1), Sci. Adv. (1), Adv. Mater. (8), J. Am. He has published more than 60 academic papers in international authoritative academic journals such as Chem. Soc. (2 papers) and Research (2 papers), and he has cited more than 8,000 times by his peers.
Article link: https://onlinelibrary.wiley.com/doi/10.1002/adma.202313638
Source: Northwestern Polytechnical University