title: High-quality sandwiched black phosphorus heterostructure and its quantum oscillations.
abstract: Two-dimensional materials such as graphene and transition metal dichalcogenides have attracted great attention because of their rich physics and potential applications in next-generation nanoelectronic devices. The family of two-dimensional materials was recently joined by atomically thin black phosphorus which possesses high theoretical mobility and tunable bandgap structure. However, degradation of properties under atmospheric conditions and high-density charge traps in black phosphorus have largely limited its actual mobility thus hindering its future applications. Here, we report the fabrication of stable sandwiched heterostructures by encapsulating atomically thin black phosphorus between hexagonal boron nitride layers to realize ultra-clean interfaces that allow a high field-effect mobility of ∼1,350 cm(2)V(-1) s(-1) at room temperature and on-off ratios exceeding 10(5). At low temperatures, the mobility even reaches ∼2,700 cm(2)V(-1) s(-1) and quantum oscillations in black phosphorus two-dimensional hole gas are observed at low magnetic fields. Importantly, the sandwiched heterostructures ensure that the quality of black phosphorus remains high under ambient conditions.
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Zefei
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Shuigang
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Condensed Matter Physics, Group of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH1211 Geneva, Switzerland.
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Weiguang
authors.initials: W
authors.lastname: Ye
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Han
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Yuheng
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Department of Physics and the William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang