Study On Electronic Transport Properties Of Phosphorene Nanoribbons Under External Field

Two-dimensional material is a nanomaterial whose electronic state is restricted to two dimensional planes.Because of its unique optical,electromagnetism and mechanical properties,it has become one of the hottest research fields of condensed matter physics.In recent years,as a type of new two-dimensional material,phosphorene has a wide range of application prospects in electron transport due to its remarkable quantum size effect,high carrier mobility and unique anisotropy.In this paper,within the tight-binding model Hamiltonian,by adopting the nonequilibrium Green's function,we have studied the electronic and transport properties of monolayer/bilayer(ML/BL)zigzag phosphorene nanoribbon(ZPNR)junctions,which are modulated by perpendicular electric field(PEF).Under the linear strain approximation,we systematically studied the electronic structures of bilayer and multilayer armchair phosphorene nanoribbons(APNRs).These studies may provide theoretical guidance for the design and application of phosphorene-based electronic devices in the future.The paper consists of five parts:In the first chapter,the research progress of new two-dimensional materials in low-dimensional and nanostructured systems are mainly introduced.Among them,the physical properties and main structures of graphene and transition metal chalcogenides are introduced in more detail.Then,the early researches,the basic physical properties and potential applications of the black phosphorus are emphasized.In the second chapter,several common methods of mesoscopic quantum transport are introduced,as well as several typical approximation methods of energy band theory are introduced.Chapters 3 and 4 are our main jobs.In the third chapter,we build three kindsof AB stacking structures for ML/BL zigzag ZPNR junctions,and study the band structures and transport properties of the monolayer/bilayer/bilayer(ML/BL/BL)and monolayer/bilayer/monolayer(ML/BL/ML)ZPNR junctions under two opposite PEFs.Our results show that the ML/BL/BL ZPNR junction may be more suitable for the usage of field effect transistor under a PEF.The PEF can be applied to distinguish the bottom-bottom and bottom-up configuration.In the fourth chapter,we investigate the band structures for AB stacking bilayer and multilayer APNRs,which are affected by the uniaxial strain along y,z direction and biaxial strain along in-plane.Further,we explore the relationship between the band gaps of the bilayer and multilayer APNRs with three kinds of uniaxial strains.Our results show that the band gap show an insulator-metal transition induced by the strain for APNRs.The four layer APNRs is most appreciable to design detectors for detecting the strains.In the last chapter,we summarize this paper,and then look forward to the research that based on the transport properties of phosphorene.