Contact-First Integration toward Pristine Metal-MoS2 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.