Work Function Engineering of Copper Sulfides for 2D Electronics

Achieving ideal metal/semiconductor junctions remains a critical challenge in advancing 2D electronics. While current approaches often rely on clean van der Waals contact interfaces to mitigate Fermi-level pinning, they offer limited tunability in achieving precise energy level alignment with 2D semiconductors. In this work, a wide range of work function modulation in copper sulfide (Cu_2−xS, 0 ≤ X < 1) electrode materials is proposed that can be achieved through an air-ambient sulfurization process. Depending on the concentration of sulfur atoms, the Cu_2−xS electrode showed considerable modulation in work function from 5.10 to 4.15 eV (ΔΦ = 950 meV). The continuous tunable work function of Cu_2−xS electrodes enables the ideal junction interface with ohmic contact properties of both n-type and p-type transition metal dichalcogenides materials. Our efficient work function engineering strategy provides an innovative way to design 2D electronics for the development of integrated electronics devices.