title: Charge transfer in crystalline germanium/monolayer MoS2heterostructures prepared by chemical vapor deposition.
abstract: Heterostructuring provides novel opportunities for exploring emergent phenomena and applications by developing designed properties beyond those of homogeneous materials. Advances in nanoscience enable the preparation of heterostructures formed incommensurate materials. Two-dimensional (2D) materials, such as graphene and transition metal dichalcogenides, are of particular interest due to their distinct physical characteristics. Recently, 2D/2D heterostructures have opened up new research areas. However, other heterostructures such as 2D/three-dimensional (3D) materials have not been thoroughly studied yet although the growth of 3D materials on 2D materials creating 2D/3D heterostructures with exceptional carrier transport properties has been reported. Here we report a novel heterostructure composed of Ge and monolayer MoS2, prepared by chemical vapor deposition. A single crystalline Ge (110) thin film was grown on monolayer MoS2. The electrical characteristics of Ge and MoS2in the Ge/MoS2heterostructure were remarkably different from those of isolated Ge and MoS2. The field-effect conductivity type of the monolayer MoS2is converted from n-type to p-type by growth of the Ge thin film on top of it. Undoped Ge on MoS2is highly conducting. The observations can be explained by charge transfer in the heterostructure as opposed to chemical doping via the incorporation of impurities, based on our first-principles calculations.
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. jyoo@lanl.gov.
authors.forename: Yung-Chen
authors.initials: YC
authors.lastname: Lin
authors.affiliation: Department of Physics, Northeastern University, Boston, MA 02115, USA and Materials Physics and Applications-11, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: Ismail
authors.initials: I
authors.lastname: Bilgin
authors.affiliation: T-4, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: Towfiq
authors.initials: T
authors.lastname: Ahmed
authors.affiliation: Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Renjie
authors.initials: R
authors.lastname: Chen
authors.affiliation: Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87110, USA.
authors.forename: Doug
authors.initials: D
authors.lastname: Pete
authors.affiliation: Department of Physics, Northeastern University, Boston, MA 02115, USA.
authors.forename: Swastik
authors.initials: S
authors.lastname: Kar
authors.affiliation: T-4, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Zhu
authors.affiliation: Materials Physics and Applications-11, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: Gautam
authors.initials: G
authors.lastname: Gupta
authors.affiliation: Materials Physics and Applications-11, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: Aditya
authors.initials: A
authors.lastname: Mohite
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. jyoo@lanl.gov.
authors.forename: Jinkyoung
authors.initials: J
authors.lastname: Yoo