Bosai Lyu,1,2 Jiajun Chen,1,2 Sen Wang,3 Shuo Lou,1,2 Peiyue Shen,1,2 Jingxu Xie,1,2 Lu Qiu,4,5,6 Izaac Mitchell,4 Can Li,1,2 Cheng Hu,1,2 Xianliang Zhou,1,2 Kenji Watanabe,7 Takashi Taniguchi,8 Xiaoqun Wang,1,2,9 Jinfeng Jia,1,2,9 Qi Liang,1,2,9 Guorui Chen,1 Tingxin Li,1,2,9 Shiyong Wang,1,2,9 Wengen Ouyang,3 Oded Hod,10 Feng Ding,4,11 Michael Urbakh,10, and Zhiwen Shi1,2,9
1) Key Laboratory of Artificial Structures and Quantum Control
(Ministry of Education), Shenyang National Laboratory for Materials
Science, School of Physics and Astronomy, Shanghai Jiao Tong
University, Shanghai 200240, China.
2) Collaborative Innovation Center of Advanced Microstructures,
Nanjing University, Nanjing 210093, China.
3) Department of Engineering Mechanics, School of Civil Engineering,
Wuhan University, Wuhan, Hubei 430072, China.
4) Department of Materials Science and Engineering, Ulsan National
Institute of Science and Technology, Ulsan 44919, South Korea.
5) Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
6) Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
7) Research Center for Functional Materials, National Institute for
Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
8) International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
9) Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai,
200240, China.
10) Department of Physical Chemistry, School of Chemistry and The
Sackler Center for Computational Molecular and Materials Science, The
Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv
University, Tel Aviv 6997801, Israel.
11)Shenzhen Institute of Advanced Technology, Chinese Academy of
Sciences, Shenzhen 518055, China.
Van der Waals encapsulation of two-dimensional materials in hexagonal
boron nitride (hBN) stacks is a promising way to create
ultrahigh-performance electronic devices. However, contemporary
approaches for achieving van der Waals encapsulation, which involve
artificial layer stacking using mechanical transfer techniques, are
difficult to control, prone to contamination and unscalable. Here we
report the transfer-free direct growth of high-quality graphene
nanoribbons (GNRs) in hBN stacks. The as-grown embedded GNRs exhibit
highly desirable features being ultralong (up to 0.25 mm), ultranarrow
(<5 nm) and homochiral with zigzag edges. Our atomistic simulations
show that the mechanism underlying the embedded growth involves
ultralow GNR friction when sliding between AA'-stacked hBN
layers. Using the grown structures, we demonstrate the transfer-free
fabrication of embedded GNR field-effect devices that exhibit
excellent performance at room temperature with mobilities of up to
4,600 cm2V-1s-1 and on-off ratios of
up to 106. This paves the way for the bottom-up fabrication
of high-performance electronic devices based on embedded layered
materials.
