Contact-First Integration toward Pristine Metal–MoS ₂ Interfaces

Interfacial engineering remains a critical challenge for realizing high-performance and reliable two-dimensional (2D) semiconductor electronics. Despite rapid advances in wafer-scale synthesis of transition metal dichalcogenides (TMDs), the formation of low-resistance and thermally stable metal-semiconductor contacts during postgrowth process continues to limit device performance and stability. Conventional fabrication routes that combine polymer-assisted transfer with subsequent metal deposition inevitably introduce interfacial contamination and structural damage, leading to strong Fermi-level pinning and elevated contact resistance. Here, we report a contact-first integration strategy that enables intrinsically clean and damage-free metal-semiconductor interfaces at scale. In this approach, prepatterned Au electrodes are laminated onto MoS₂ while it remains on the growth substrate, forming pristine contacts that are preserved throughout subsequent transfer and device fabrication. MoS₂ field-effect transistors fabricated using this method exhibit a synergistic performance enhancement with an Ion/Ioff ratio exceeding 10⁸, a peak field-effect mobility of 42.1 cm² V⁻¹ s⁻¹, and a low contact resistance of ∼934 Ω·μm on a SiO₂ substrate. Importantly, these contact-first devices maintain stable electrical characteristics after annealing at 300 °C, demonstrating excellent thermal robustness compatible with BEOL integration. Structural and spectroscopic characterizations further support the formation of an intimate van der Waals contact at the Au/MoS₂ interface. These results establish the contact-first strategy as a reliable pathway toward high-performance and thermally robust electronics based on 2D semiconductors.