Liu Can, Li Zehui, Qiao Ruixi, Wang Qinghe, Zhang Zhibin, Liu Fang, Zhou Ziqi, Shang Nianze, Fang Hongwei, Wang Meixiao, Liu Zhongkai, Feng Zuo, Cheng Yang, Wu Heng, Gong Dewei, Liu Song, Zhang Zhensheng, Zou Dingxin, Fu Ying, He Jun, Hong Hao, Wu Muhong, Gao Peng, Tan Ping-Heng, Wang Xinqiang, Yu Dapeng, Wang Enge, Wang Zhu-Jun, Liu Kaihui
State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China.
Department of Physics, Renmin University of China, Beijing, China.
Nat Mater. 2022 Nov;21(11):1263-1268. doi: 10.1038/s41563-022-01361-8. Epub 2022 Sep 15.
The production of large-area twisted bilayer graphene (TBG) with controllable angles is a prerequisite for proceeding with its massive applications. However, most of the prevailing strategies to fabricate twisted bilayers face great challenges, where the transfer methods are easily stuck by interfacial contamination, and direct growth methods lack the flexibility in twist-angle design. Here we develop an effective strategy to grow centimetre-scale TBG with arbitrary twist angles (accuracy, <1.0°). The success in accurate angle control is realized by an angle replication from two prerotated single-crystal Cu(111) foils to form a Cu/TBG/Cu sandwich structure, from which the TBG can be isolated by a custom-developed equipotential surface etching process. The accuracy and consistency of the twist angles are unambiguously illustrated by comprehensive characterization techniques, namely, optical spectroscopy, electron microscopy, photoemission spectroscopy and photocurrent spectroscopy. Our work opens an accessible avenue for the designed growth of large-scale two-dimensional twisted bilayers and thus lays the material foundation for the future applications of twistronics at the integration level.
制备具有可控角度的大面积扭曲双层石墨烯（TBG）是其大规模应用的前提条件。然而，大多数现有的制备扭曲双层的策略都面临巨大挑战，其中转移方法容易受到界面污染的阻碍，而直接生长方法在扭曲角设计上缺乏灵活性。在此，我们开发了一种有效的策略来生长具有任意扭曲角（精度<1.0°）的厘米级TBG。通过从两个预旋转的单晶Cu(111)箔片进行角度复制以形成Cu/TBG/Cu三明治结构，实现了精确的角度控制，通过定制开发的等势面蚀刻工艺可以从该结构中分离出TBG。通过综合表征技术，即光谱学、电子显微镜、光电子能谱和光电流能谱，明确地展示了扭曲角的准确性和一致性。我们的工作为大规模二维扭曲双层的设计生长开辟了一条可行的途径，从而为未来集成级别的扭曲电子学应用奠定了材料基础。
