Electronic structure and carrier mobilities of twisted graphene helix
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Date
2020
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Publisher
Elsevier
Abstract
Density functional theory based calculations have been carried out to investigate the effect of twisting on electronic band structures and carrier mobilities of three prototypes of armchair graphene nanoribbons (AGNRs) within the fixed boundary conditions. It is found that twisting causes a modification in the bandgap values and the overall shape of band structures. The values of longitudinal acoustic deformation potential (DP) are found to be higher than the torsional acoustic DP values. The torsional strain is also found to have a profound effect on effective mass and mobilities of given AGNRs. The hole mobility of hydrogen passivated N = 8 AGNRs is found to be comparable with the carrier mobility of intrinsic graphene. The electron mobility of N = 8 AGNRs can be further increased with fluorine passivation. The width, passivation, and extent of twisting together determine n-type or p-type behavior of AGNRs. Fluorine passivated AGNRs are predicted to be potential candidates for mechanical and high-frequency switching. Our results suggest that twisting of AGNRs can be an effective mean for tuning their band structure and carrier mobility for applications in high-speed switching devices. 2020 Elsevier B.V.