Electrical properties of separated zigzag graphene nanoribbon devices with methyl chain adsorption

Zigzag graphene nanoribbon demonstrates significant capabilities in electronic transport, and the separation of graphene nanoribbons through the adsorption of atoms or groups holds considerable research value. In this work, we employed density functional theory combined with the non-equilibrium Green's function method to investigate the structure and electronic properties of graphene nanoribbons with methyl adsorption and hydrogen chain adsorption. Firstly, based on the figures of local device density of states and transmission pathways , the region where methyl is adsorbed forms a bonding state between the methyl group and carbon atoms. This bonding state restricts the migration of pi-electrons within the nanoribbon, achieving a more stable separation effect. Additionally, analyses of I-V curves, band structure diagrams, and transmission pathways reveal that the edge effects of zigzag graphene nanoribbon exhibit different behaviors in two molecular separation devices. The methyl chain separator demonstrated the most favorable performance, with little difference in electron transfer between the edge and the interior. Finally, methyl adsorption is obviously superior to hydrogen chain adsorption in terms of separation and reduction of scattering effect.