Modulation of Electronic Behaviors of InSe Nanosheet and Nanoribbons: The First‐Principles Study

First-principles study on the electronic properties of biphenylene, net-graphene, graphene+, and T-graphene based nanoribbons

Since the successful separation of graphene, carbon materials with the excellent physical and chemical properties have attracted the interest of a large number of researchers. In this paper, density functional theory combined with non-equilibrium Green's function is used to systematically study the electronic structures of two-dimensional biphenylene, net-graphene, graphene+ and T-graphene, and to reveal the electron transport properties of net-graphene nanodevices under asymmetric regulation. The results show that biphenylene, net-graphene, graphene+, and T-graphene all show metallic properties, in which biphenylene and net-graphene show anisotropy, while graphene+ and T-graphene show isotropy. In addition, for the one-dimensional new carbon based nanoribbons, except for the armchair-edged net-graphene and biphenylene nanoribbons, which exhibit semiconductor properties and a band gap value of 0.08 eV, the rest of the carbon nanoribbons display metal properties. Interestingly, two of them showed a tendency to oscillate and decrease the band gap value with increasing width, while BPN-2 biphenylene nanoribbons directly changed from exhibiting semiconductor to metallic properties with increasing width combination with no oscillation. The electronic transport properties of net-graphene nanoribbons based nanodevice models for electrons transform along zigzag and armchair directions are systematically studied. An obvious negative differential resistance characteristic along the armchair and zigzag directions can be found. Overall, these interesting results show that these new net-graphene nanodevices have good practical application prospects in future electronic nanodevices.

Carbon phosphide nanosheets and nanoribbons: insights on modulating their electronic properties by first principles calculations

A carbon phosphide (CP) monolayer, a 2D structure derived from the same 3-fold coordination found both in graphene and phosphorene, has been successfully synthesized in an experiment recently. In this paper, we investigated the modulation of electronic structures and transport characteristics of 2D nanosheets and quasi-1D nanoribbons of CP nanomaterials in the α-phase by using first-principles density functional theory simulation. The calculated band structures show that the band gap of 2D CP nanosheets progressively increases as the uniform biaxial strain changes from compression to stretching. However, the biaxial strain cannot change the indirect band gap behavior of the original 2D CP nanosheet. In addition, the band structures of quasi-1D nanoribbons with different styles of H-passivated zigzag edges have also been studied. The results show that the H-passivated zigzag PC ribbons with two P edges are semiconductors with indirect band gaps, and the gaps decrease with increasing width of ribbons. However, the H-passivated CP nanoribbons with one P-atom terminated edge in combination with one P-atom edge, and H-passivated CC nanoribbons with two C-atom terminated edges display metallic behaviors. The semi-conductive or metallic behaviors of zigzag CP nanoribbons can be explained by presenting the wave function of their energy band around the Fermi level. Finally, the electronic transport properties of different CP nanoribbon based nanojunctions are studied in which arise the interesting negative differential resistance or rectification effects in their current-voltage characteristic curves.