Theoretical Study For Electronic And Transport Properties Of Novel Porous Graphenes And Corresponding Porous Graphene Nanoribbons

The novel porous graphenes is a class of two-dimensional honeycombstructures with periodic porous and large π-conjugate system. Comparing withthe band structure of pure graphene, the porous graphenes show semiconductorproperties, which can be applied in many fields, such as light catalytic carriers,hydrogen storage materials, nanoelectronic materials, etc. Owing to the peculiargeometrical and electronic structures of porous graphenes, we construct andinvestigate the electronic and electron transport properties of a series oftwo-dimensional hydrocarbon porous n-Benzo-CMPs (n=3,4,5) sheets and theirBN codoped derivatives, BN-n-Benzo-CMPs using density-functional theory(DFT) calculations and the non-equilibrium Green’s function (NEGF), as well asone-dimensional (1D) porous graphene nanoribbons.The study of electronic properties show that all of the two-dimensionalhydrocarbon porous graphenes and BN codoped derivatives are semiconductorswith direct band gaps (0.57-1.75eV) in Г point. They possess nanoscale pores,and the pore size varies from0.368to1.293nm. The band gaps decrease with thepore size enlarging. The BN doped can decrease the band gap, too. All of theone-dimensional porous graphene nanoribbons are also semiconductors withdirect band gaps (0.11~2.00eV) at Г point. For one-dimensional porous graphenenanoribbons, either armchair-nanoribbons or zigzag-nanoribbons, theenlargement of pore size and BN codoping can decrease the band gap. In addition,the width of nanoribbons is another impact on the band gap.The study of the transport properties display that the two-probe system ofBN-3-Benzo-CMP has stronger current response and stronger transmission peak,as a result it show better electrical conductivity. In all of the one-dimensional porous graphene nanoribbons, the two-probe systemBN-3ZGNR (W=4) shows the strongest current response and transmission peaks.Comparing with BN-3-Benzo-CMP, BN-3ZGNR (W=4) has similar conductivity.Therefore, BN-3-Benzo-CMP and BN-3ZGNR (W=4) will become a potentiallow-electronics materials.