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

Abstract

Abstract2D 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 ION/IOFF 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 V0.25Mo0.75S2 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.