Structural, electronic, and electromechanical properties of MoSSe/blue phosphorene heterobilayer

Xiaobao Li,Changwen Mi,Weijie Hao,Huanlin Zhou,Xiaotian Wang

doi:10.1063/1.5122755

Xiaobao Li, Changwen Mi + Show 3 more

Open Access

https://doi.org/10.1063/1.5122755

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Abstract

Two-dimensional (2D) materials attract considerable interest due to their outstanding electronic and mechanical properties. Although extensive efforts have been made on seeking of new kinds of 2D materials, individual ones can hardly offer all required properties for practical applications in nanoelectronics and optoelectronics. To integrate the advantages of each individual component, in this work, we predict the structural and electromechanical properties of 2D van der Waals (vdW) heterobilayers constructed with single-layer Janus transition metal dichalcogenides and blue phosphorus (e.g., SMoSe/BlueP and SeMoS/BlueP) by means of density-functional theory (DFT) based calculations. The vdW interactions were carefully taken into account by employing the DFT-DF correction functional. It is found that the proposed vdW heterobilayers are dynamically stable with enhanced elastic moduli. The SeMoS/BlueP heterobilayer is shown as a type-I semiconductor with an indirect bandgap of 1.55 eV, and SMoSe/BlueP is also a type-I semiconductor with a slightly larger indirect bandgap of 1.76 eV. In addition, the piezoelectronic response of the heterobilayers was also carefully explored. In particular, the out-of-plane piezoelectric response of SeMoS/BlueP that is characterized by the piezoelectric coefficient e311(d311) gets enhanced compared to the Janus MoSSe monolayer. Our findings demonstrate a great potential for their applications in energy harvesting and sensors at the nanoscale.

Highlights

Two-dimensional (2D) materials have been an active research field for the past decade due to their potential applications among optoelectronics/nanoelectronics, solar cells, photocatalysis, and so on.1,2 Besides typical planar honeycomb families such as carbon-based materials and nitrides (e.g., IIInitrides4), a few nonplanar/puckered monolayers [e.g., transition metal dichalcogenides (TMDs),5 silicene,6 and black phosphorene7 (BlackP)] attracted considerable attention in recent years because of their intriguing electronic and mechanical properties
To integrate the advantages of each individual component, in this work, we predict the structural and electromechanical properties of 2D van der Waals heterobilayers constructed with single-layer Janus transition metal dichalcogenides and blue phosphorus (e.g., SMoSe/blue phosphorene (BlueP) and SeMoS/BlueP) by means of density-functional theory (DFT) based calculations
It is worthwhile to point out that stacking patterns (a) and (f) possess similar levels of energy for the SeMoS/BlueP heterobilayer [see Fig. S2(a) of the supplementary material], one may still conclude that the stacking pattern (a) is the most stable one due to the presence of clear imaginary mode in the corresponding phonon dispersion spectra for the stacking pattern (f) [Fig. S3(f) of the supplementary material]

Summary

INTRODUCTION

Two-dimensional (2D) materials have been an active research field for the past decade due to their potential applications among optoelectronics/nanoelectronics, solar cells, photocatalysis, and so on. Besides typical planar honeycomb families such as carbon-based materials (e.g., graphene3) and nitrides (e.g., IIInitrides4), a few nonplanar/puckered monolayers [e.g., transition metal dichalcogenides (TMDs), silicene, and black phosphorene (BlackP)] attracted considerable attention in recent years because of their intriguing electronic and mechanical properties. The Rashba splitting at the Γ-point for the uppermost valence band was found and may be enhanced by applying the external electric field and strain field.21,22 Thanks to this asymmetric structure in the vertical dimension, Dong et al showed the intrinsic out-of-plane dipoles based on the ab initio calculations.. Monolayer phosphorene has been engineered to be piezoelectric by chemically modifying its surface with oxygen atoms.37 Despite these encouraging progresses, most 2D materials show either vanished or very weak out-of-plane piezoelectric response (e.g., III-V buckled monolayers and Janus TMD monolayers), which is highly desirable in electromechanical-coupling based nanodevices. As a matter of fact, both TMD monolayers and BlueP(BlackP) have been frequently used as elementary blocks to build vdW heterostructures.45 Inspired by these ideas, in this letter, we intend to investigate the elastic, electronic, and piezoelectric response of a few heterobilayers consisting of both nonpiezoelectric and piezoelectric components, e.g., SMoSe/BlueP and SeMoS/BlueP.

COMPUTATIONAL DETAILS

Structure and stability

Elastic properties

Electronic band structures

Piezoelectricity

CONCLUSIONS