Theoretical Calculation Of Electronic Structures And Transport Properties Of Borophene, Phosphorene And Their Heterojunction Nanoribbon

The discovery of graphene has attracted worldwide attention,But because of its zero-energy gap,researchers began to look for other two-dimension materials,subsequently,silene,germanene,phosphorene and borophene were successfully prepared in experiments.These two-dimension materials have potential applications in thermodynamics,optics,electronic devices and other fields.With the improvement of calculation methods and modern high performance computing ability,researchers can use the first-principles method to achieve the prediction of two-dimensional material structure and performance that is difficult to achieve in current experimental equipment or conditions.In this paper,the structure and properties of borophene,phosphorene nanoribbon and heterojunction are discussed based on the first principle of density functional theory and non-equilibrium green function method.It mainly includes three aspects.(1)The properties of borophene nanoribbon with different edge passivstion were studied systematically.The structures of borophene nanoribbon without hydrogen passivation and borophene nanoribbon with hydrogen passivation in two periodic directions were analyzed by band structure and state density diagram.It is found that the spin characteristics of the nanoribbon can be adjusted by the edge hydrogen passivation.Their stability was also analyzed by using the binding energy,It was found that hydrogen passivation makes the borophene nanoribbon more stable.Then to investigate the transport properties of hydrogenated borophene nanoribbon.Finally,their current-voltage characteristic curves are studied.Negative differential resistance effect appears.This provides a reference for the design of electronic devices.(2)The geometrical structure and band structure of phosphorene nanoribbon with different edge oxygen passivation were studied systematically.The results show that different widths have significant influence on the structure and electronic properties of phosphene nanoribbon.For APNRs,the band gap decreases gradμAlly with the increase of nanoribbon width.For ZPNRs,with the increase of nanoribband width,ZPNRs transforms from direct bandgap semiconductor to metal properties.The effect of nanoribbon width on the transport performance was also studied and the current-voltage characteristic curve was analyzed.The results show that some width phosphorene nanoribbon has negative differential resistance effect.This provides a theoretical basis for the future research on the transport performance of phosphorene nanoribbon and the design of related electronic devices.(3)The heterostructure of borophene/phosphorene was studied systematically.The geometrical structures and electronic band structures of monolayer borophene,monolayer phosphorene and heterojunctios with different distances between layers were analyzed.The results show that the band gap can be adjusted by adjusting the distance between heterostructure layers.The changes before and after heterojunction were compared.Then the transport properties of the heterojunction with different electrodes were studied.The results show that the selected different electrode has a significant effect on the transport property of the heterojunction.The heterostructure was selected as the electrode to show the best transport performance Heterojunction with the interlayer distance of 2.65? has the best transport performance.