Bandgap renormalization and work function tuning in MoSe2/hBN/Ru(0001) heterostructures

Qiang Zhang; Yuxuan Chen; Chendong Zhang; Chi-Ruei Pan; Mei-Yin Chou; Changgan Zeng; Chih-Kang Shih

doi:10.1038/ncomms13843

Bandgap renormalization and work function tuning in MoSe₂/hBN/Ru(0001) heterostructures

Nat Commun. 2016 Dec 14:7:13843. doi: 10.1038/ncomms13843.

Authors

Qiang Zhang^{1

2

3}, Yuxuan Chen¹, Chendong Zhang¹, Chi-Ruei Pan⁴, Mei-Yin Chou^{4

5

6}, Changgan Zeng^{2

3

7

8}, Chih-Kang Shih¹

Affiliations

¹ Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA.
² Hefei National Laboratory for Physical Sciences at the Microscale (HFNL), CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Hefei 230026, China.
³ Department of Physics, University of Science and Technology of China, Hefei 230026, China.
⁴ School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
⁵ Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
⁶ Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
⁷ International Center for Quantum Design of Functional Materials (ICQD), HFNL, University of Science and Technology of China, Hefei 230026, China.
⁸ Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.

Abstract

The van der Waals interaction in vertical heterostructures made of two-dimensional (2D) materials relaxes the requirement of lattice matching, therefore enabling great design flexibility to tailor novel 2D electronic systems. Here we report the successful growth of MoSe₂ on single-layer hexagonal boron nitride (hBN) on the Ru(0001) substrate using molecular beam epitaxy. Using scanning tunnelling microscopy and spectroscopy, we found that the quasi-particle bandgap of MoSe₂ on hBN/Ru is about 0.25 eV smaller than those on graphene or graphite substrates. We attribute this result to the strong interaction between hBN/Ru, which causes residual metallic screening from the substrate. In addition, the electronic structure and the work function of MoSe₂ are modulated electrostatically with an amplitude of ∼0.13 eV. Most interestingly, this electrostatic modulation is spatially in phase with the Moiré pattern of hBN on Ru(0001) whose surface also exhibits a work function modulation of the same amplitude.

Publication types

Research Support, Non-U.S. Gov't