title: Highly Stable, Dual-Gated MoS2 Transistors Encapsulated by Hexagonal Boron Nitride with Gate-Controllable Contact, Resistance, and Threshold Voltage.
abstract: Emerging two-dimensional (2D) semiconductors such as molybdenum disulfide (MoS2) have been intensively studied because of their novel properties for advanced electronics and optoelectronics. However, 2D materials are by nature sensitive to environmental influences, such as temperature, humidity, adsorbates, and trapped charges in neighboring dielectrics. Therefore, it is crucial to develop device architectures that provide both high performance and long-term stability. Here we report high performance of dual-gated van der Waals (vdW) heterostructure devices in which MoS2 layers are fully encapsulated by hexagonal boron nitride (hBN) and contacts are formed using graphene. The hBN-encapsulation provides excellent protection from environmental factors, resulting in highly stable device performance, even at elevated temperatures. Our measurements also reveal high-quality electrical contacts and reduced hysteresis, leading to high two-terminal carrier mobility (33-151 cm(2) V(-1) s(-1)) and low subthreshold swing (80 mV/dec) at room temperature. Furthermore, adjustment of graphene Fermi level and use of dual gates enable us to separately control contact resistance and threshold voltage. This novel vdW heterostructure device opens up a new way toward fabrication of stable, high-performance devices based on 2D materials.
authors.affiliation: †Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea.
authors.forename: Gwan-Hyoung
authors.initials: GH
authors.lastname: Lee
authors.forename: Xu
authors.initials: X
authors.lastname: Cui
authors.forename: Young Duck
authors.initials: YD
authors.lastname: Kim
authors.forename: Ghidewon
authors.initials: G
authors.lastname: Arefe
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: §KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Korea.
authors.forename: Chul-Ho
authors.initials: CH
authors.lastname: Lee
authors.forename: Fan
authors.initials: F
authors.lastname: Ye
authors.affiliation: ⊥National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: ⊥National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: #Department of Physics and Applied Physics, Harvard University, Cambridge, Massachusetts 02139, United States.
authors.forename: Philip
authors.initials: P
authors.lastname: Kim
authors.forename: James
authors.initials: J
authors.lastname: Hone
keywords: MoS2; contact resistance; graphene; hexagonal boron nitride; threshold voltage; two-dimensional materials; van der Waals heterostructure