Theoretical investigation on electronic properties and carrier mobilities of armchair graphyne nanoribbons

- The band gaps of armchair graphyne nanoribbons are larger than those of graphynes.
- Some graphyne nanoribbons have both high hole and electron mobilities.
- Graphyne nanoribbons are superior to graphene nanoribbons.
- The sparse crystal orbitals are responsible for the high carrier mobilities.

A sufficiently large band gap, both high hole and electron mobilities are essential for high speed complementary circuits with low power dissipation. Based on HSE06 density functional, seven types of armchair graphyne nanoribbons and two-dimensional graphynes are investigated theoretically. For the two-dimensional graphynes, only γ-graphyne has a band gap larger than 0.4 eV. The quantum confinements in the one-dimensional nanoribbons open or increase the band gaps of the corresponding two-dimensional counterparts. This is crucial for high on/off ratio in electronic devices. In some nanoribbons with high percentage of sp hybridized carbon atoms, the frontier crystal orbitals are sparse, which result in small deformation potential constants and large carrier mobilities. Some one-dimensional structures, especially for 14,14,18-graphyne nanoribbons, have both high hole and electron mobilities, which are more than one order of magnitude larger than those of the armchair graphene nanoribbons, indicating their potential applications in high speed electronic devices.

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