Interfacial Engineering of Degenerately Doped V0.25Mo0.75S2 for Improved Contacts in MoS2 Field Effect Transistors

Abstract 2D transition‐metal dichalcogenide semiconductors such as MoS 2 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 MoS 2 films is reported, leading to improved performance of field effect transistors. The transistor performance of monolayer pure MoS 2 is initially characterized by its I ON / I OFF ratio (10 6 ), carrier density (≈10 12 cm −2 ), and mobility (≈10 cm 2 Vs −1 ), and the Schottky barrier height (SBH) of conventional metallic Au contact of MoS 2 (≈215 meV). Then, a CVD‐grown degenerately‐doped monolayer of alloy V 0.25 Mo 0.75 S 2 is introduced between Au and MoS 2 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.