Graphene-Assisted Antioxidation of Tungsten Disulfide Monolayers: Substrate and Electric-Field Effect

Kyungnam Kang; Kyle Godin; Young Duck Kim; Shichen Fu; Wujoon Cha; James Hone; Eui-Hyeok Yang

doi:10.1002/adma.201603898

Graphene-Assisted Antioxidation of Tungsten Disulfide Monolayers: Substrate and Electric-Field Effect

Adv Mater. 2017 May;29(18). doi: 10.1002/adma.201603898. Epub 2017 Feb 24.

Authors

Kyungnam Kang¹, Kyle Godin¹, Young Duck Kim², Shichen Fu¹, Wujoon Cha², James Hone², Eui-Hyeok Yang¹

Affiliations

¹ Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
² Department of Mechanical Engineering, Columbia University, New York, NY, 10027, USA.

PMID: 28234414
DOI: 10.1002/adma.201603898

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 WS₂ on SiO₂ , graphene/SiO₂ , and on graphene suspended in air is elucidated. While WS₂ on a SiO₂ substrate begins oxidation within weeks, epitaxially grown WS₂ on 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 WS₂ on a SiO₂ substrate by a local electric field created using an atomic force microscope tip is also demonstrated.

Keywords: WS2/graphene heterostructures; antioxidation of WS2 monolayers; epitaxial growth; surface electric field.