Programme

P.53 -- Poster, NCTP-43

Date: Wednesday, 1 August 2018

Time: 08:30 - 10:00

The effects of external electric fields on the energy gap and its properties of bilayer zigzag graphene nano-ribbons

Huynh Huyen Tran, Nguyen Thi My The

College of Natural Sciences, Can Tho University

As we have known that graphene is a superior material for conductivity, durability and thinness. However, graphene has a major problem with its properties, it doesnot have large enough the energy gap to control the on/off current like semiconductor material. We investigate the effects of external electric fields on the electronic properties of bilayer armchair graphene nano-ribbons. Using atomistic simulations with Tight Binding calculations and the Non-equilibrium Green's function formalism, we demonstrate that (i) in semi-metallic structures, vertical fields impact more effectively than transverse fields in terms of opening larger bandgap, showing a contrary phenomenon compared to that demonstrated in previous studies in bilayer zigzag graphene nano-ribbons; (ii) in some semiconducting structures, if transverse fields just show usual effects as in single layer armchair graphene nano-ribbons where the bandgap is suppressed when varying the applied potential, vertical fields exhibit an anomalous phenomenon that the bandgap can be enlarged. Although the combined effect of two fields does not enlarge the bandgap as found in bilayer zigzag graphene nano-ribbons, it shows that the mutual effect can be useful to reduce faster the bandgap in semiconducting bilayer armchair graphene nano-ribbons. These results are important to fully understand the effects of electric fields on bilayer graphene nano-ribbons (AB stacking) and also suggest appropriate uses of electric gates with different edge orientations. The desire to control this barrier width in the most effective way possible to meet the graphene application needs into electronic technology in the future.

Presenter: Huynh Huyen Tran