title: Graphene-Assisted Antioxidation of Tungsten Disulfide Monolayers: Substrate and Electric-Field Effect.
abstract: Transition metal dichalcogenides (TMDs) have emerged as promising materials to complement graphene for advanced optoelectronics. However, irreversible degradation of chemical vapor deposition-grown monolayer TMDs via oxidation under ambient conditions limits applications of TMD-based devices. Here, the growth of oxidation-resistant tungsten disulfide (WS2) monolayers on graphene is demonstrated, and the mechanism of oxidation of WS2on SiO2, graphene/SiO2, and on graphene suspended in air is elucidated. While WS2on a SiO2substrate begins oxidation within weeks, epitaxially grown WS2on suspended graphene does not show any sign of oxidation, attributed to the screening effect of surface electric field caused by the substrate. The control of a local oxidation of WS2on a SiO2substrate by a local electric field created using an atomic force microscope tip is also demonstrated.
authors.affiliation: Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
authors.forename: Kyungnam
authors.initials: K
authors.lastname: Kang
authors.affiliation: Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Godin
authors.affiliation: Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA.
authors.forename: Young Duck
authors.initials: YD
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
authors.forename: Shichen
authors.initials: S
authors.lastname: Fu
authors.affiliation: Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA.
authors.forename: Wujoon
authors.initials: W
authors.lastname: Cha
authors.affiliation: Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA.
authors.forename: James
authors.initials: J
authors.lastname: Hone
authors.affiliation: Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
authors.forename: Eui-Hyeok
authors.initials: EH
authors.lastname: Yang
keywords: WS2/graphene heterostructures; antioxidation of WS2 monolayers; epitaxial growth; surface electric field