van Hove Source for Ultralow Power Field-Effect Transistors

Field-effect transistors (FETs) with sub-60 mV/decade subthreshold swing (SS) at room temperature are highly sought after for enabling next-generation ultralow-power integrated circuits (ICs). We present a van Hove source (VHS) FET that exploits the steeply declining density of states (DOS) at the van Hove singularity in a one-dimensional (1D) semiconductor to overcome the Boltzmann limit on switching performance in conventional FETs. The VHS FETs built on individual semiconducting carbon nanotubes (CNT) exhibit a room temperature SS of 49 mV/decade. This steep switching behavior is achieved by electrostatically tuning the source Fermi level through a control gate. Compared with the 22-nanometer-node silicon FETs, a comparable on-state current is obtained in our VHS FETs with a 450 nm gate length but at a reduced supply voltage of 0.5 V (versus 0.75 V for silicon). VHS engineering may offer a generalizable pathway for 1D semiconductors to lower SS and even construct steep-slope transistors that simultaneously deliver ultralow power, high performance, and scalability.