Interlayer electron modulation in van der Waals heterostructures assembled by stacking monolayer MoS2 onto monolayer graphene with different electron transfer ability

Zhenping Wang; Qing Cao; Kai Sotthewes; Yalei Hu; Hyeon S Shin; Siegfried Eigler

doi:10.1039/d1nr03708k

Interlayer electron modulation in van der Waals heterostructures assembled by stacking monolayer MoS₂ onto monolayer graphene with different electron transfer ability

Nanoscale. 2021 Sep 23;13(36):15464-15470. doi: 10.1039/d1nr03708k.

Authors

Zhenping Wang¹, Qing Cao², Kai Sotthewes³, Yalei Hu², Hyeon S Shin¹, Siegfried Eigler²

Affiliations

¹ Department of Chemistry, Low-Dimensional Carbon and 2D Materials Center, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea. shin@unist.ac.kr.
² Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany. siegfried.eigler@fu-berlin.de.
³ Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands.

PMID: 34505854
DOI: 10.1039/d1nr03708k

Abstract

Achieving tunable optoelectronic properties and clarifying interlayer interactions are key challenges in the development of 2D heterostructures. Herein, we report the feasible modulation of the optoelectronic properties of monolayer MoS₂ (1L-MoS₂) on three different graphene monolayers with varying ability in extracting electrons. Monolayer oxygen-functionalized graphene (1L-oxo-G, a high amount of oxygen of 60%) with a work function (WF) of 5.67 eV and its lowly oxidized reduction product, namely reduced-oxo-G (1L-r-oxo-G, a low amount of oxygen of 0.1%), with a WF of 5.85 eV serving as hole injection layers significantly enhance the photoluminescence (PL) intensity of MoS₂, whereas pristine monolayer graphene (1L-G) with a work function (WF) of 5.02 eV results in PL quenching of MoS₂. The enhancement in the PL intensity is due to increase of neutral exciton recombination. Furthermore, 1L-r-oxo-G/MoS₂ exhibited a higher increase (5-fold) in PL than 1L-oxo-G/MoS₂ (3-fold). Our research can help modulate the carrier concentration and electronic type of 1L-MoS₂ and has promising applications in optoelectronic devices.