title: Direct Observation of 2D Electrostatics and Ohmic Contacts in Template-Grown Graphene/WS2Heterostructures.
abstract: Large-area two-dimensional (2D) heterojunctions are promising building blocks of 2D circuits. Understanding their intriguing electrostatics is pivotal but largely hindered by the lack of direct observations. Here graphene-WS2heterojunctions are prepared over large areas using a seedless ambient-pressure chemical vapor deposition technique. Kelvin probe force microscopy, photoluminescence spectroscopy, and scanning tunneling microscopy characterize the doping in graphene-WS2heterojunctions as-grown on sapphire and transferred to SiO2with and without thermal annealing. Both p-n and n-n junctions are observed, and a flat-band condition (zero Schottky barrier height) is found for lightly n-doped WS2, promising low-resistance ohmic contacts. This indicates a more favorable band alignment for graphene-WS2than has been predicted, likely explaining the low barriers observed in transport experiments on similar heterojunctions. Electrostatic modeling demonstrates that the large depletion width of the graphene-WS2junction reflects the electrostatics of the one-dimensional junction between two-dimensional materials.
authors.forename: Changxi
authors.identifier: 0000-0002-7463-0289
authors.initials: C
authors.lastname: Zheng
authors.forename: Qianhui
authors.initials: Q
authors.lastname: Zhang
authors.forename: Bent
authors.initials: B
authors.lastname: Weber
authors.affiliation: Network for Computational Nanotechnology (NCN), Purdue University , West Lafayette, Indiana 47906, United States.
authors.forename: Hesameddin
authors.initials: H
authors.lastname: Ilatikhameneh
authors.affiliation: Network for Computational Nanotechnology (NCN), Purdue University , West Lafayette, Indiana 47906, United States.
authors.forename: Fan
authors.initials: F
authors.lastname: Chen
authors.affiliation: Network for Computational Nanotechnology (NCN), Purdue University , West Lafayette, Indiana 47906, United States.
authors.forename: Harshad
authors.initials: H
authors.lastname: Sahasrabudhe
authors.affiliation: Network for Computational Nanotechnology (NCN), Purdue University , West Lafayette, Indiana 47906, United States.
authors.forename: Rajib
authors.initials: R
authors.lastname: Rahman
authors.affiliation: Department of Electrical and Electronic Engineering, University of Melbourne , Victoria 3010, Australia.
authors.forename: Shiqiang
authors.initials: S
authors.lastname: Li
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.forename: Jack
authors.initials: J
authors.lastname: Hellerstedt
authors.forename: Yupeng
authors.identifier: 0000-0003-2351-5579
authors.initials: Y
authors.lastname: Zhang
authors.forename: Wen Hui
authors.initials: WH
authors.lastname: Duan
authors.affiliation: Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215123, People's Republic of China.
authors.forename: Qiaoliang
authors.initials: Q
authors.lastname: Bao
authors.forename: Michael S
authors.initials: MS
authors.lastname: Fuhrer
keywords: electrostatics; graphene; heterostructure; ohmic contacts; transition-metal dichalcogenides