Ultrashort Vertical-Channel van der Waals Semiconductor Transistors

Atomically thin 2D van der Waals semiconductors are promising candidates for next-generation nanoscale field-effect transistors (FETs). Although large-area 2D van der Waals materials have been successfully synthesized, such nanometer-length-scale devices have not been well demonstrated in 2D van der Waals semiconductors. Here, controllable nanometer-scale transistors with a channel length of ≈10 nm are fabricated via vertical channels by squeezing an ultrathin insulating spacer between the out-of-plane source and drain electrodes, and the feasibility of high-density and large-scale fabrication is demonstrated. A large on-current density of ≈70 µA µm^-1 nm^-1 at a source-drain voltage of 0.5 V and a high on/off ratio of ≈10⁷-10⁹ are obtained in ultrashort 2D vertical channel FETs with monolayer MoS₂ synthesized through chemical vapor deposition. The work provides a promising route toward the complementary metal-oxide-semiconductor-compatible fabrication of wafer-scale 2D van der Waals transistors with high-density integration.