Bridging synthesis and controllable doping of monolayer 4-inch transition-metal dichalcogenides single crystals with record-breaking electron mobility

Abstract Epitaxial growth and controllable doping of wafer-scale atomically thin semiconductor single crystals are two central tasks to tackle the scaling challenge of transistors. Despite considerable efforts have been devoted, addressing such crucial issues simultaneously under two-dimensional (2D) confinement is yet to be realized. Here we design an ingenious epitaxial strategy to synthesize record-breaking 4-inch Fe-doped transition-metal dichalcogenides (TMDCs) single crystals on industry-compatible c-plane sapphire without miscut angle. Atomically thin transistors with the highest recorded electron mobility (~231 cm2 V−1 s−1) and remarkable on/off current ratio (~109) are fabricated based on 4-inch Fe-MoS2 single crystals, due to the ultralow contact resistance (~489 Ω µm) and subthreshold swing (~95 mV dec−1). In-depth characterizations and theoretical calculations reveal that the introduction of Fe significantly decreases the formation energy of parallel steps on sapphire surfaces and contributes to the edge-nucleation of unidirectional alignment TMDCs domains (>99%), as well as the modulation of band structures. This work represents a substantial leap in terms of bridging synthesis and doping of wafer-scale 2D semiconductor single crystals without the need for substrate miscut, which should promote the further device downscaling and extension of Moore’s law.