Germanene/2D-AlP van der Waals heterostructure: Tunable structural and electronic properties

Md Rayid Hasan Mojumder,Md Sherajul Islam,Jeongwon Park

doi:10.1063/5.0023448

Abstract

Developing van der Waals heterostructures (vdWHs) utilizing vertical mounting of diverse two-dimensional (2D) materials is an efficient way of achieving favorable characteristics. Using first-principles calculations, we demonstrated the geometric configurations and electronic properties of germanene/2D-AlP vdWHs. We considered four high symmetric patterns that show a bandgap opening in the heterostructures of 200 meV–460 meV. The incorporation of spin-orbital coupling reduces the bandgap by 20 meV–90 meV. Both direct and indirect bandgaps were found from these high symmetric patterns, depending on the structural patterns. The charge density distribution and the partial density of states confirmed that germanene was the property builder of the heterostructure, in which 2D-AlP could be a decent substrate. The heterostructure bandgap can be widely tuned in the range 0 meV–500 meV by changing the interlayer separation between the two monolayers. The application of strain and external electric fields also significantly tailored the electronic structures of the heterostructures. Intriguingly, an exceptionally high carrier mobility of more than 1.5 × 105 cm2 V−1 s−1 was observed, which outperforms compared to other studies on germanene heterostructures. All these promising properties make the germanene/2D-AlP heterostructure a viable candidate for FETs, strain sensors, nanoelectronics, and spintronic devices.

Highlights

Captivating emerging properties of two-dimensional (2D) materials, mostly derived from group-IV, have recently become a fascinating research area
The exotic properties of 2D materials, including high carrier mobility, profound surface activity, large quantum spin hall effect, and distinct mechanical strength,[15,16] make them well adorned for next-generation application in nanoelectronics
The development of van der Waals heterostructures using two different 2D materials in vertical stacking has opened up new possibilities for bandgap engineering and charge transfer between layers.[19–25]

Summary

Introduction

Captivating emerging properties of two-dimensional (2D) materials, mostly derived from group-IV, have recently become a fascinating research area Some of those properties of 2D materials can rarely be obtained in their three-dimensional parent materials.[1,2,3,4,5,6,7] experimental synthesis of almost all the groupIV 2D materials (i.e., graphene, silicene, germanene, stanene, and others) has been conducted.[8,9,10,11,12,13,14] The exotic properties of 2D materials, including high carrier mobility, profound surface activity, large quantum spin hall effect, and distinct mechanical strength,[15,16] make them well adorned for next-generation application in nanoelectronics. A slight twist in the repeated superlattice pattern (moiré pattern32) of the vdWHs often creates new topological phases.[23,24] Varieties of extraordinary functionalities can be achieved by deploying these vdWHs in the realization of tunneling transistors, optoelectronics, and spintronic devices.[33–36]

Methods

Results

Conclusion