Samsung Advanced Institute of Technology

A high Schottky barrier height (SBH) due to Fermi-level pinning (FLP) at a metal？semiconductor junction increases energy consumption and degrades electronic devices¹. Although a van der Waals (vdW) contact between a metal and 2D semiconductor without FLP is theoretically feasible, interactions such as the effects of interface defects in direct metal contact^2-3 have prevented this from being realized in practice. We demonstrate a metal-deposition process for forming an ideal (interaction- and defect-free) vdW metal contact between a pure metal and 2D semiconductor using a buffer layer. Experimentally, the vdW metal contact obeys the Schottky？Mott rule; the FLP strength is ？0.92. A comparison between vdW and direct metal contacts reveals significant differences in the interface gap distance, band bending, and electrical characteristics. The vdW Au contact produced excellent device characteristics in p-type WSe₂ field-effect transistors (FETs): superior stability, a large on/off ratio (>10⁶), high mobility (~155 cm²/Vs), low contact resistance (2R_c = 2.5 kΩ μm), and low hole SBH (~60 meV). The effectiveness of the ideal vdW metal contact without FLP in FETs has been verified for various transition metal dichalcogenide FETs: the contact method is exceptionally reliable and convenient for electrical-device fabrication using 2D vdW materials.