Huge hole injection in tungsten dichalcogenide heterostructures without electric gating: a DFT study

Abstract

Van der Waals heterostructures based on transition metal dichalcogenides, TMDs, provide a versatile platform for tailoring electronic properties through interlayer charge transfer, CT. Precise control of CT is essential because it directly determines the electronic structure and carrier concentration in atomically thin materials. Recently, the concept of a chemical capacitor has been proposed as a route to achieving exceptionally high carrier densities through CT across insulating separator layers. Here, we extend this concept to van der Waals heterostructures by investigating TMD hBN OX, oxidizer, systems using density functional theory, DFT. Following the screening of candidate TMDs and electron acceptors, XeF2 and KrF2 were identified as suitable acceptors exhibiting type III broken gap band alignment with WS2 and WSe2, respectively. Periodic DFT calculations of large supercells reveal CT corresponding to hole concentrations of up to 0.23 h+ and 0.35 h+ per W atom in WS2 hBN XeF2 and WSe2 hBN KrF2 heterostructures, respectively. The resulting charge redistribution demonstrates that noble gas fluorides provide an efficient route for noncontact engineering of carrier density in TMD heterostructures, offering a new strategy for tuning correlated electronic phases in two dimensional materials.