Density Functional Theory Study Of The Electronic Properties Of Doped Two-dimensional Borophene Heterojunction

In recent years,with the quickly development of science and technology,in order to meet the needs of the future miniaturization of the microelectronics and optoelectronics industries,the size and integration of electronic devices continue to increase.Low-dimensional materials have become a hotspot of materials research by researchers today.So far,graphene,black phosphorus,molybdenum disulfide,transition metal group carbides,transition metal disulfide,boron nitride,borophene and other materials have been successfully prepared in the experiment.The properties of these materials are all different.There are always deficiencies and defects in the properties of a single material.In order to make two-dimensional materials have more application prospects in the field of nanomaterials,researchers adjust the physical properties of two-dimensional materials by assembling different two-dimensional materials to construct heterojunctions.In this paper,the borophene/graphene heterogeneous(sB-Gr)was taken as the research object,and the following two aspects were studied:(1)In this chapter,the effects of N and P doping on the geometrical structure and electronic properties of borophene/graphene heterojunction are systematically studied by density functional theory calculation and analysis.The results show that:by comparison with the metallic properties of the complete borophene/graphene heterojunctions,nitrogen-and phosphorus-doped borophene/graphene heterojunctions both show semiconducting properties.Molecular dynamics simulation at room temperature further demonstrated the dynamic stability of the related systems.The research results can afford reference for the application of borophene/graphene heterostructure in new two-dimensional semiconductor materials.(2)The adsorption of hydrogen or fluorine atoms on the graphene side(sB-Gr H₂,sB-Gr F₂)and borophene side(sBH₃-Gr,sBF₃-Gr)of borophene/graphene heterojunction based on triangular lattice was studied by density functional theory.The stability of sB-Gr H₂,sB-Gr F₂,sBH₃-Gr and sBF₃-Gr was analyzed by molecular dynamics simulation.The results show that the three structures of sB-Gr H₂,sB-Gr F₂,and sBF₃-Gr are stable at the temperature of 300K,while the structural integrity of sBH₃-Gr cannot be maintained at the temperature of300K.Therefore,only the electronic properties of sB-Gr H₂,sB-Gr F₂,and sBF₃-Gr are analyzed.The calculation shows that both sB-Gr H₂and sB-Gr F₂are direct bandgap semiconductors,while the band structure diagram of sBF₃-Gr shows indirect bandgap semiconductor.At the same time,it is calculated that the single-layer graphene and borophene structures adsorb hydrogen and fluorine atoms in a triangular lattice manner.When graphene adsorbs hydrogen atoms,it is an indirect band gap semiconductor,while graphene fluorine atoms cannot make it a semi-metal with zero band gap.The regulation of properties is semi-conductor properties,but its semi-metallic properties become metallic properties.The adsorption of fluorine atoms on a single-layer borophene can adjust its metal properties to semiconductor properties with a small band gap,but the adjustment of the band gap by the single-layer borene by fluorine atoms is not obvious for the adjustment of the heterojunction band gap.It can provide more theoretical basis for the application of two-dimensional sB-Gr heterojunction materials in semiconductor materials.