•  
  •  
 
Nano Research

Article Title

Edge induced band bending in van der Waals heterojunctions: A first principle study

Authors

Yang Ou, Beijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory for Advanced Energy Materials and Technologies, University of Science and Technology Beijing, Beijing 100083, China
Zhuo Kang, Beijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory for Advanced Energy Materials and Technologies, University of Science and Technology Beijing, Beijing 100083, China State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
Qingliang Liao, Beijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory for Advanced Energy Materials and Technologies, University of Science and Technology Beijing, Beijing 100083, China State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
Zheng Zhang, Beijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory for Advanced Energy Materials and Technologies, University of Science and Technology Beijing, Beijing 100083, China State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
Yue Zhang, Beijing Advanced Innovation Center for Materials Genome Engineering, Beijing Key Laboratory for Advanced Energy Materials and Technologies, University of Science and Technology Beijing, Beijing 100083, China State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China

Keywords

edge band bending, imbalance charge, electrostatic doping, transition metal dichalcogenides (TMDCs) van der Waals (vdW) heterojunction, first principle

Abstract

The dangling bond free nature of two-dimensional (2D) material surface/interface makes van der Waals (vdW) heterostructure attractive for novel electronic and optoelectronic applications. But in practice, edge is unavoidable and could cause band bending at 2D material edge analog to surface/interface band bending in conventional three-dimensional (3D) materials. Here, we report a first principle simulation on edge band bending of free standing MoS2/WS2 vdW heterojunction. Due to the imbalance charges at edge, S terminated edge causes upward band bending while Mo/W terminated induces downward bending in undoped case. The edge band bending is comparable to band gap and could obviously harm electronic and optoelectronic properties. We also investigate the edge band bending of electrostatic doped heterojunction. N doping raises the edge band whereas p doping causes a decline of edge band. Heavy n doping even reverses the downward edge band bending at Mo/W terminated edge. In contrast, heavy p doping doesn’t invert the upward bending to downward. Comparing with former experiments, the expected band gap narrowing introduced by interlayer potential gradient at edge is not observed in our free-standing structures and suggests substrate’s important role in this imbalance charge induced phenomenon.

Graphical Abstract

Publisher

Tsinghua University Press

Share

COinS