title: Building Large-Domain Twisted Bilayer Graphene with van Hove Singularity.
abstract: Twisted bilayer graphene (tBLG) with van Hove Singularity (VHS) has exhibited novel twist-angle-dependent chemical and physical phenomena. However, scalable production of high-quality tBLG is still in its infancy, especially lacking the angle controlled preparation methods. Here, we report a facile approach to prepare tBLG with large domain sizes (>100 μm) and controlled twist angles by a clean layer-by-layer transfer of two constituent graphene monolayers. The whole process without interfacial polymer contamination in two monolayers guarantees the interlayer interaction of the π-bond electrons, which gives rise to the existence of minigaps in electronic structures and the consequent formation of VHSs in density of state. Such perturbation on band structure was directly observed by angle-resolved photoemission spectroscopy with submicrometer spatial resolution (micro-ARPES). The VHSs lead to a strong light-matter interaction and thus introduce ∼20-fold enhanced intensity of Raman G-band, which is a characteristic of high-quality tBLG. The as-prepared tBLG with strong light-matter interaction was further fabricated into high-performance photodetectors with selectively enhanced photocurrent generation (up to ∼6 times compared with monolayer in our device).
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.|Academy for Advanced Interdisciplinary Studies, Peking University , Beijing 100871, P. R. China.
authors.forename: Zhenjun
authors.initials: Z
authors.lastname: Tan
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Yin
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford , Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Cheng
authors.initials: C
authors.lastname: Chen
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.|Academy for Advanced Interdisciplinary Studies, Peking University , Beijing 100871, P. R. China.
authors.forename: Luzhao
authors.initials: L
authors.lastname: Sun
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Jinxiong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.|Academy for Advanced Interdisciplinary Studies, Peking University , Beijing 100871, P. R. China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Sun
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford , Parks Road, Oxford OX1 3PU, United Kingdom.|State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences , 865 Changning Road, Shanghai 200050, P. R. China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Yang
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford , Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Hailin
authors.initials: H
authors.lastname: Peng
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Zhongfan
authors.initials: Z
authors.lastname: Liu
keywords: interlayer coupling; photocurrent enhancement; twisted bilayer graphene; van Hove singularity