Electronic Structures of Twisted Bilayer InSe/InSe and Heterobilayer Graphene/InSe.

Xiaojing Yao,Xiuyun Zhang

doi:10.1021/acsomega.1c01562

Abstract

Building vertical van der Waals heterojunctions between two-dimensional layered materials has become a promising strategy for modulating the properties of two-dimensional materials. Herein, we investigate the electronic structures of non-twisted/twisted bilayer InSe/InSe and heterobilayer graphene/InSe (Gr/InSe) by employing density functional theory calculations. For twisted bilayer InSe/InSes, their interlayer distances and band gaps are almost identical but a bit larger than those of the AB-stacking one due to the spontaneous polarization. Differently, the band gaps of twisted Gr/InSe are found to vary with the rotation angles. Our results provide an effective way to tune the electronic properties of two-dimensional materials.

Highlights

To date, two-dimensional (2D) layered materials, such as graphene (Gr),[1] silicene,[2] transition metal dichalcogenides (TMDs),[3] and black phosphorene (BP),[4] have attracted great interest due to their excellent properties such as high carrier mobilities, strong quantum confinement effects, high on−off current ratios, etc., which enable them to be promising candidates in electronic and spintronic devices
As for bilayer BP, it is found that the anisotropy of its electronic structure and optical transitions can be tuned by gating with an interlayer twist angle of 90°
We investigate the structural and electronic properties of InSe/InSe and graphene/InSe (Gr/InSe) van der Waals (vdW) heterostructures with different rotation angles by firstprinciples calculations

Summary

INTRODUCTION

Two-dimensional (2D) layered materials, such as graphene (Gr),[1] silicene,[2] transition metal dichalcogenides (TMDs),[3] and black phosphorene (BP),[4] have attracted great interest due to their excellent properties such as high carrier mobilities, strong quantum confinement effects, high on−off current ratios, etc., which enable them to be promising candidates in electronic and spintronic devices. Theoretical and experimental explorations demonstrated that the heterostructures composed of MoX2 and WX2 (X = S, Se, or Te) have type-II band alignments.[23,24] Theoretical studies indicated that twisted bilayers of Gr/MoS2 show significant differences in band structures from the non-twisted ones with the appearance of the crossover between direct and indirect band gap and gap variations.[25,26] In addition, when coupling graphene with BP, on one hand, their respective properties are preserved in the composed heterostructure; on the other hand, the band structure of the two-sided monolayer material can be tuned by the application of an external electrical field perpendicular to the 2D plane.[27,28]. For Gr/InSe, their electronic structures are found to vary with different rotation angles

COMPUTATIONAL METHODS

RESULTS AND DISCUSSION

■ REFERENCES

CONCLUSIONS

Phosphorene

■ ACKNOWLEDGMENTS