High-Performance and Low-Power Sub-5 nm Field-Effect Transistors Based on the Isolated-Band Semiconductor

To suppress the subthreshold swing (SS) and overcome the 60 mV/dec limit, we theoretically propose a strategy using isolated-band semiconductors as the channel. Monolayer LaBr₂ has a unique isolated band around the Fermi level that cuts off the carrier transport of high-energy regions in the off-state while maintaining thermionic emission in the on-state. Even at a supply voltage of 0.50 V, the armchair-oriented LaBr₂ field-effect transistors (FETs) meet the international standards for high-performance and low-power applications by minimizing the gate length to 3 and 4 nm, respectively. Specifically, the 5 nm armchair-oriented LaBr₂ FET brings the SS to 50 mV/dec with a high on-state current of 1057 μA/μm. The zigzag-oriented LaBr₂ FETs can meet high-performance requirements with gate length lowered to 4 nm. The LaBr₂ FETs also exhibit excellent spin filtering and negative differential resistance effects. This finding provides a practical solution for extending Moore’s law to sub-5 nm scales.