By Katsuhiro Tomioka

A transistor has been demonstrated that operates at low supply voltages by exceeding a theoretical limit. The finding opens up avenues to the development of integrated circuits that have extremely low power consumption. See Letter p.91

Field-effect transistors (FETs) are used in integrated circuits that form part of commonplace devices such as smartphones, tablets and laptops. Improving the performance of these items depends crucially on miniaturizing FETs. But miniaturization cannot continue forever — it faces a fundamental thermionic limit below which a FET's turn-on performance (rapid switching on at low supply voltage) cannot improve without a commensurate increase in power consumption. On page 91 of this issue, Sarkar et al.1 demonstrate a tunnel-FET (TFET) that combines an atomically thin, two-dimensional semiconducting crystal with a 3D germanium substrate and shows excellent turn-on performance at only 0.1 volts.