The Transport Properties Of Single-layer Phosphorene Under Strain And C₃N Under The Action Of Edge Chemical Modification

With the rapid development of nanoelectronics and molecular electronics,nanoscale circuits composed of nanoscale devices have also been developing in the direction of smaller size,higher integration and higher efficiency.Therefore,the properties of two-dimensional nanomaterials have been highly required.Because traditional silicon materials can not break through the physical limit,silicon materials are no longer meeting the higher requirements of electronic devices.Graphene was successfully prepared in 2004.With its unique physical and chemical properties,graphene has attracted a great deal of attention in condensed matter physics and computational chemistry.Graphene was once considered to be the first choice to replace traditional silicon materials in the future.However,due to the zero band gap of intrinsic graphene,the application of graphene in the preparation of electronic devices is greatly limited.In recent years,more and more two-dimensional nanomaterials have been found,and have been successfully prepared,such as phosphorene and C3N and so on.The eigen phosphorenes has a direct band gap of about 1.52eV,which makes up the deficiency of graphene in the preparation of nano devices,but the phosphorene will be oxidized in the air or soaked in water,and can be degraded under the action of light.The eigen C3N has a direct band gap of about 0.39eV and has good stability.The band structure and electron transport properties of single-layer phosphorene and monolayer C3N are studied in this paper.Firstly,we investigate the Goos-Hanchen(GH)shift for ballistic electrons(i)reflected from a step-like inhomogeneity of strain,and(ii)transmitted through a mono-layer phosphoresce junction consisting of a positive strained region and two normal regions(or a normal region and two negative strained regions).Refraction occurs at the interface between the unstrained/positive-strain(negative-strain/unstrained),in analogy with optical refraction.The critical angle is different for different strengths and directions of the strains.The critical angles for electrons tunneling through unstrained/positive-strain junction can even decrease to zero when the positive strain exceeds a critical value.For the mono-layer phosphorene junction consisting of a positive strain region and two normal regions(or a normal region and two negative strain regions),we find that the GH shifts resonantly depends on the middle region width.The resonant values and the plus-minus sign of the displacement can be controlled by the incident angle,incident energy and the strain.Then we selected some typical nonmetallic atom as the edge saturation atom,and studied the influence of the edge saturated atoms on the band structure of the C3N C-C side zigzag nanoribbon(CCA).First,we calculated the formation energies of different nanoribbon,and proved that these nanoribbon are stable.Secondly,we use the first principle calculation method based on ATK software to predict the performance of new nanoribbons using hydrogen atoms(H),boron atoms(B),oxygen atoms(O)and fluorine atoms(F)to saturate the CCA nanoribbon,the band gap of the new nanoribbon is direct band gap after the saturation of boron atoms.The other three atoms are indirectly banded after saturation.The new nanoribbon with silicon atom(Si),phosphrous atom(P)and sulfur atom(S)saturates a new nanoribbon with a new highest valence band(HVB).The new nanoribbons after the sulfur atom saturates the new lowest conduction band(LCB).Finally,we studied the transport properties of the semiconductor nanorbbon and the eigen nanorbbon,the IV curves showed an obvious negative differential resistance(NDR)effect.In particular,the maximum current reached by 40 ?A is achieved by C3N-O nanorbbon and eigen C3N nanorbbon.In conclusion,we systematically studied the effects of strain on Goos-Hanchen shifts of mono-layer phosphorene and the influence of edge chemical modification on the electronic structure and transport properties of C3N nanorbbon.Our research results provide a theoretical basis for the application of phosphorene and C3N preparation of electronic devices.