Modular van der Waals MOSFETs through layer-by-layer chalcogen substitutions

Abstract

In two-dimensional transition-metal dichalcogenides (TMDCs), the local electrostatic field of the chalcogen p -orbitals dictates the crystal field splitting of the transition metal d -orbitals, stabilizing diverse electronic states from semiconducting and semimetallic to exotic topological phases. On-demand substitution of the lattice chalcogens is therefore an efficient route to tuning TMDC electronic phases. Here, we custom-molded van der Waals (vdW) heterostructures by layer-by-layer vapor-phase chalcogen substitution starting from p -type WSe 2 multilayers into which we locally inscribed insulating WO x , n -type WS 2 , and semimetallic WTe 2 . This spatially precise conversion seamlessly integrated distinct electronic phases, both vertically and laterally, into modular vdW semiconductor heterostructures that are otherwise inaccessible. As a demonstration, we integrated WO x /WSe 2 local gate stacks to build ultrascaled metal oxide–semiconductor field effect transistors (MOSFETs), achieving an unprecedented subthreshold swing at subnanometer equivalent oxide thickness.

The authors' abstract, as published at the source. Science, 2026 · DOI ↗