Impact of Elastic Phonon Dephasing on the Switching Performance of Armchair Graphene Nanoribbon Field Effect Transistor

Armchair graphene nanoribbon field-effect transistors are promising candidates for nextgeneration nanoelectronics due to their tunable bandgap and high carrier mobility. In this work, a nearest-neighbor tight-binding Hamiltonian within a self-consistent non-equilibrium Green’s function (NEGF) framework is employed to investigate the impact of elastic phonon dephasing on the switching performance of dual-gate AGNR-FETs. Phonon dephasing is modeled using a scalar coupling parameter and analyzed under two limiting cases: momentum-conserving (MC) and momentum-relaxing (MR) scattering. The effects on key device metrics, including the on/off current ratio and subthreshold swing, are systematically evaluated. The results demonstrate that MC dephasing severely degrades switching behavior by increasing off-state leakage and worsening subthreshold characteristics, whereas MR dephasing preserves transistor-like operation with relatively minor performance degradation. Transmission analysis reveals that MC dephasing smears the transport gap, whereas MR dephasing preserves energy selectivity. These findings highlight the critical role of dephasing mechanisms in AGNR-based devices and emphasize the necessity of incorporating realistic phonon scattering models for reliable nanoscale transistor design.