Paving the way for mechanical fabrication of graphether nanoribbons

With exceptionally high tensile strength and electrical conductivity and transparency, graphene – a single atomic layer of carbon and the thinnest material known to exist – has rapidly become a valuable component in semiconductors, electronics, electric batteries and composites. However, to remedy the allotrope’s zero band gap, several graphene derivatives have been synthesized in recent years, and many more have been theoretically proposed. One of these is graphether, which has high electron mobility and excellent thermodynamic stability – ideal traits for application in nanoelectronics.

Graphene nanoribbons have two basic edge structures – zigzag and armchair – on which their electronic properties depend. Notably, graphether exhibits significantly greater in-plane stiffness along the direction of the latter edge structure, providing the possibility to mechanically fabricate armchair-edged graphether nanoribbons (AGENRs).

Jiang et al. investigate the electronic structure properties of AGENRs through first-principles calculations, finding they are symmetry-dependent.

“Symmetry … is crucial to the electronic properties of these nanoribbons,” said author Yandong Guo. “It could even trigger their indirect-direct bandgap transition and semiconducting-metallic transition.”

The research reveals an odd-even bandgap oscillation with the width when the nanoribbon is narrow, but that fades as the ribbon widens. When one edge of an AGENR is partially passivated by hydrogen, the electronic structure asymmetry will lead to the semiconducting-metallic transition.

These findings may help inform modulability of the electronic structure of graphether nanoribbons and be useful in band engineering of related devices and the design of heterojunctions based on 2D nanostructures.

“Although graphether nanoribbons show excellent properties, they haven’t been experimentally fabricated yet.” said Guo. “We look forward to the progress of future experimental works, as well as new discoveries of graphene derivatives.”

Source: “Symmetry-dependent electronic structure transition in graphether nanoribbons,” by Yue Jiang, Yandong Guo, Hongli Zeng, Liyan Lin, and Xiaohong Yan, AIP Advances (2022). The article can be accessed at https://aip.scitation.org/doi/10.1063/5.0077309 .