title: Tunable Electrical and Optical Characteristics in Monolayer Graphene and Few-Layer MoS2 Heterostructure Devices.
abstract: Lateral and vertical two-dimensional heterostructure devices, in particular graphene-MoS2, have attracted profound interest as they offer additional functionalities over normal two-dimensional devices. Here, we have carried out electrical and optical characterization of graphene-MoS2 heterostructure. The few-layer MoS2 devices with metal electrode at one end and monolayer graphene electrode at the other end show nonlinearity in drain current with drain voltage sweep due to asymmetrical Schottky barrier height at the contacts and can be modulated with an external gate field. The doping effect of MoS2 on graphene was observed as double Dirac points in the transfer characteristics of the graphene field-effect transistor (FET) with a few-layer MoS2 overlapping the middle part of the channel, whereas the underlapping of graphene have negligible effect on MoS2 FET characteristics, which showed typical n-type behavior. The heterostructure also exhibits a strongest optical response for 520 nm wavelength, which decreases with higher wavelengths. Another distinct feature observed in the heterostructure is the peak in the photocurrent around zero gate voltage. This peak is distinguished from conventional MoS2 FETs, which show a continuous increase in photocurrent with back-gate voltage. These results offer significant insight and further enhance the understanding of the graphene-MoS2 heterostructure.
authors.forename: Servin
authors.initials: S
authors.lastname: Rathi
authors.forename: Inyeal
authors.initials: I
authors.lastname: Lee
authors.forename: Dongsuk
authors.initials: D
authors.lastname: Lim
authors.forename: Jianwei
authors.initials: J
authors.lastname: Wang
authors.affiliation: §Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ochiai
authors.affiliation: §Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Aoki
authors.affiliation: ∥Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: ∥Advanced Materials Laboratory, 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 Material Science and Engineering, Yonsei University, Seoul 120-749, Korea.
authors.forename: Gwan-Hyoung
authors.initials: GH
authors.lastname: Lee
authors.affiliation: #Creative Research Center for Graphene Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700, Korea.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Yu
authors.affiliation: ∇Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: Philip
authors.initials: P
authors.lastname: Kim
authors.forename: Gil-Ho
authors.initials: GH
authors.lastname: Kim
keywords: 2D semiconductor; Schottky barrier; field-effect transistor; graphene; heterostructure; molybdenum disulfide