Strong interlayer hybridization in the aligned SnS2/WSe2 hetero-bilayer structure

Jihene Zribi,Julien Chaste,Abdelkarim Ouerghi,Anlian Pan,Lama Khalil,Emmanuel Lhuillier,Maria C Asensio,José Avila,Thibault Brulé,Debora Pierucci,Biyuan Zheng

doi:10.1038/s41699-019-0109-3

Abstract

The combination of monolayers of different two-dimensional (2D) materials into van der Waals hetero-bilayer structures creates unprecedented physical phenomena, acting as a powerful tool for future devices. Understanding and exploiting these phenomena hinge on knowing the electronic structure and the hybridization of hetero-bilayer structures. Here, we show strong hybridization effects arising between the constitutive single layers of a SnS2/WSe2 hetero-bilayer structure grown by chemical vapor deposition. Surprisingly, the valence band maximum position of WSe2 is moved from the K point for the single layer WSe2 to the Γ point for the aligned SnS2/WSe2 hetero-bilayer. Additionally, a significant photoluminescence quenching is observed for the SnS2/WSe2 hetero-bilayer structure with respect to the WSe2 monolayer. Using photoluminescence spectroscopy and nano-angle-resolved photoemission spectroscopy techniques, we demonstrate that the SnS2/WSe2 heterostructure present a type-II band alignment. These findings directly answer many outstanding questions about the electronic band structure and the band offset of SnS2/WSe2 hetero-bilayers for envisaging their applications in nanoelectronics.

Highlights

Two-dimensional (2D) layered semiconductors with few atomic layer thicknesses and tunable bandgaps have attracted a significant interest in the last years
Since it is straightforward to evaluate if the constitutive single layers of the heterostructure retain their electronic properties after the layer stacking or they are strongly perturbed, we have investigated the punctual band structure of selected areas on our sample
We demonstrate that the valence band maximum (VBM) of WSe2 changes its position in the Brillouin zone (BZ) from the K to the Γ point when moving from the single layer to the hetero-bilayer structure

Summary

Introduction

Two-dimensional (2D) layered semiconductors with few atomic layer thicknesses and tunable bandgaps have attracted a significant interest in the last years. We have provided a precise electronic characterization for the WSe2 single layer and the SnS2/WSe2 hetero-bilayer structures, which are simultaneously present on the same flake after the growth.

Results

Conclusion