Bismuthene nanoribbon topological field-effect transistor: a DFT-NEGF-based study

Topological field-effect transistors (TFETs) based on two-dimensional materials have emerged as promising candidates for low-power electronic applications. In this study, we explore the electronic and transport properties of a bismuthene nanoribbon TFET using density functional theory combined with the nonequilibrium Green’s function formalism. We systematically examine the effects of edge passivation, channel length variation, and vacancy defects on the device’s transfer characteristics. Our results reveal that edge passivation mitigates trivial edge states, thereby enhancing robustness against structural defects and reducing the threshold voltage. Moreover, increasing the channel length effectively suppresses the tunneling leakage current during the off state, leading to an improvement in the subthreshold swing. We also evaluate key performance metrics—such as on/off ratio, capacitance, delay time, and dynamic energy dissipation—and demonstrate compliance with the IRDS standards for 10 nm gate length technology. This work highlights the significance of topological features in device performance and offers practical insights for designing next-generation energy-efficient nanoelectronic devices.