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

作　　者：Yang Ou Zhuo Kang Qingliang Liao Zheng Zhang Yue Zhang 

机构地区：[1]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 [2]State Key Laboratory for Advanced Metals and Materials,School of Materials Science and Engineering,University cf Science and Technology Beijing,Beijing 100083,China

出　　处：《Nano Research》2020年第3期701-708,共8页纳米研究（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.51991340,51991342,51527802,51972022,51722203,and 51672026);the Overseas Expertise Introduction Projects for Discipline Innovation(No.B14003);the National Key Research and Development Program of China(Nos.2016YFA0202701 and 2018YFA0703503);the Natural Science Foundation of Beijing Municipality(No.Z180011);the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-18-004A2 and FRF-TP-18-001C1).

摘　　要：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.

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

分 类 号：TB30[一般工业技术—材料科学与工程]