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

TL;DR

This study demonstrates the growth of MoSe2 on hBN/Ru(0001) and reveals how substrate interactions and Moiré patterns influence its electronic properties, including band gap reduction and work function modulation.

Contribution

It provides new insights into how substrate interactions and Moiré patterns affect the electronic structure of MoSe2 in heterostructures.

Findings

MoSe2 on hBN/Ru has a 0.25 eV smaller quasi-particle gap than on graphene or graphite.

The electronic structure and work function of MoSe2 are electrostatically modulated by the Moiré pattern.

The work function modulation amplitude is approximately 0.13 eV and is spatially in phase with the Moiré pattern.

Abstract

Here we report the successful growth of MoSe2 on single layer hexagonal boron nitride (hBN) on Ru(0001) substrate by using molecular beam epitaxy. We investigated the electronic structures of MoSe2 using scanning tunneling microscopy and spectroscopy. Surprisingly, we found that the quasi-particle gap of the 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. The surface of MoSe2 exhibits Moir\'e pattern that replicates the Moir\'e pattern of hBN/Ru. 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 Moir\'e pattern of hBN on Ru(0001) whose surface also exhibits a work function modulation of the same amplitude.