Quenching the bandgap of two-dimensional semiconductors with a perpendicular electric field
Perpendicular electric fields can tune the electronic band structure of atomically thin semiconductors. In bilayer graphene, which is an intrinsic zero-gap semiconductor, a perpendicular electric field opens a finite bandgap. So far, however, the same
principle could not be applied to control the properties of a broader class of 2D materials because the required electric fields
are beyond reach in current devices. To overcome this limitation, we design double ionic gated transistors that enable the application of large electric fields of up to 3 V/nm. Using such devices, we continuously suppress the bandgap of few-layer semiconducting transition metal dichalcogenides (that is, bilayer to heptalayer WSe2) from 1.6 V to zero. Our results illustrate an excellent level of control of the band structure of 2D semiconductors.
Daniil Domaretskiy, Marc Philippi, Marco Gibertini, Nicolas Ubrig, Ignacio Gutiérrez-Lezama and Alberto F. Morpurgo
Nature Nanotechnology volume 17, 1078 (2022)