MOCVD‐Grown MoS ₂ Wafers as a Transfer‐Free Platform for Top‐Gate Devices via Dry Interface Engineering

We uncover the electronic origin of hidden interfacial doping in monolayer MoS 2 single‐crystal wafers grown on sapphire by metal–organic chemical vapor deposition (MOCVD) and establish a transfer‐free top‐gate device platform. Despite structural perfection, as‐fabricated devices exhibit degenerate electron doping and lack a clear off state. Hall measurements quantify an interfacial electron density of 2.7 × 10 12 cm −2 , evidencing substantial charge transfer across the nominal van der Waals interface. Interface‐sensitive spectroscopy, lateral force microscopy, and thermal desorption analysis reveal a buried sulfate‐derived layer accompanied by a water‐like interfacial structure that acts as an intrinsic electron donor. A purely dry H 2 /Ar annealing process selectively removes these species, suppressing charge transfer and restoring intrinsic FET characteristics without transfer or wet processing. Through this dry interface engineering approach, we demonstrate MOCVD‐grown single‐crystal MoS 2 wafers as a robust, transfer‐free platform for the reliable evaluation of intrinsic gate stacks and device performance.