Interfacial Engineering of Degenerately Doped V_0.25Mo_0.75S₂ for Improved Contacts in MoS₂ Field Effect Transistors

2D transition-metal dichalcogenide semiconductors such as MoS₂ are identified as a platform for next-generation electronic circuitries. However, the progress toward industrial applications is still lagging due to imperfections of wafer-scale deposition techniques and in-contact parasitic impedance affecting device integration in large circuits and systems. Here, on contact engineering of large-scale, chemical vapor deposition (CVD) grown monolayer MoS₂ films is reported, leading to improved performance of field effect transistors. The transistor performance of monolayer pure MoS₂ is initially characterized by its I_ON/I_OFF ratio (10⁶), carrier density (≈10¹² cm^-2), and mobility (≈10 cm² Vs^-1), and the Schottky barrier height (SBH) of conventional metallic Au contact of MoS₂ (≈215 meV). Then, a CVD-grown degenerately-doped monolayer of alloy V_0.25Mo_0.75S₂ is introduced between Au and MoS₂ of a modified transistor, reducing the SBH to ≈100 meV. The reduced contact resistance (≈50%) of the device with an atomically thin contact interface complies with the theoretical model and is free from Fermi-level pinning effects. It is resilient to the high temperatures that are characteristic of physical metallization methods and is readily scalable.