MOCVD-Grown MoS<sub>2</sub> Wafers as a Transfer-Free Platform for Top-Gate Devices via Dry Interface Engineering.

Li, Shuhong; Chang, Juiteng; Atsumi, Keisuke; Matsumoto, Kosei; Tanaka, Itsuki; Nishimura, Tomonori; Kanahashi, Kaito; Nagata, Takahiro et al. · Adv Mater · 2026

basic_science · Level V

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Abstract

We uncover the electronic origin of hidden interfacial doping in monolayer MoS<sub>2</sub> 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<sup>12</sup> cm<sup>-2</sup>, 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<sub>2</sub>/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<sub>2</sub> wafers as a robust, transfer-free platform for the reliable evaluation of intrinsic gate stacks and device performance.