Tunable Schottky barrier in graphene/graphene-like germanium carbide van der Waals heterostructure

Sake Wang,Minglei Sun,Chongdan Ren,Hongyu Tian,Jin Yu,Yujing Xu,Jyh-Pin Chou,Changlong Sun

doi:10.1038/s41598-019-40877-z

Abstract

The structural and electronic properties of van der Waals (vdW) heterostructrue constructed by graphene and graphene-like germanium carbide were investigated by computations based on density functional theory with vdW correction. The results showed that the Dirac cone in graphene can be quite well-preserved in the vdW heterostructure. The graphene/graphene-like germanium carbide interface forms a p-type Schottky contact. The p-type Schottky barrier height decreases as the interlayer distance decreases and finally the contact transforms into a p-type Ohmic contact, suggesting that the Schottky barrier can be effectively tuned by changing the interlayer distance in the vdW heterostructure. In addition, it is also possible to modulate the Schottky barrier in the graphene/graphene-like germanium carbide vdW heterostructure by applying a perpendicular electric field. In particular, the positive electric field induces a p-type Ohmic contact, while the negative electric field results in the transition from a p-type to an n-type Schottky contact. Our results demonstrate that controlling the interlayer distance and applying a perpendicular electric field are two promising methods for tuning the electronic properties of the graphene/graphene-like germanium carbide vdW heterostructure, and they can yield dynamic switching among p-type Ohmic contact, p-type Schottky contact, and n-type Schottky contact in a single graphene-based nanoelectronics device.

Highlights

Ever since Geim and Novoselov demonstrated the first isolation of graphene (G) in 20041, two-dimensional (2D) material has been attracting much attention since its superior properties[2,3,4,5,6] such as ultrahigh mobility of charge carriers at room temperature[7], extreme mechanical strength[8], superior thermal conductivities[9], and high optical transmittance[10]
There has been rapidly growing interest in atomic-scale vertical van der Waals heterostructures made from a combination of G and other 2D semiconducting materials, such as G/MoS237–40, G/phosphorene[41,42,43,44,45], G/arsenene[46,47], G/blue phosphorene[48,49], and G/g-GaN50
Padilha et al.[41] demonstrated that by applying a perpendicular E-field, it was possible to control the Schottky barrier height (SBH) of heterostructures constructed by combining monolayer and bilayer phosphorene with G. Encouraged by this investigation, we explored the effect of an external E-field on the electronic properties of the most stable G/germanium carbide (GeC) van der Waals (vdW) heterostructure in our study

Summary

Introduction

Ever since Geim and Novoselov demonstrated the first isolation of graphene (G) in 20041, two-dimensional (2D) material has been attracting much attention since its superior properties[2,3,4,5,6] such as ultrahigh mobility of charge carriers at room temperature[7], extreme mechanical strength[8], superior thermal conductivities[9], and high optical transmittance[10]. We are unaware of any previous systematic studies on the electronic properties of layered G/GeC heterostructures, which are the focus of this investigation.

Results

Conclusion