Near-Ideal van der Waals NbSe₂ Contacts for WSe₂ CMOS Electronics

Reliable, low-resistance contacts remain a central bottleneck in two-dimensional (2D) semiconductor devices, where Fermi-level pinning (FLP) at metal-semiconductor interfaces limits carrier injection and masks intrinsic transport. Here, we demonstrate that metallic van der Waals (vdW) contacts based on transferred NbSe₂ enable near-ideal p-type operation in WSe₂ field-effect transistors. Devices with NbSe₂ contacts exhibit clear p-type characteristics, ohmic behavior, and high on/off ratios, in contrast to conventional high-work-function metal contacts. Temperature-dependent measurements reveal a reduced Schottky barrier height of ∼0.06 eV, compared to ∼0.26 eV for Pt contacts. Four-point-probe measurements confirm a low contact resistance and channel-dominated transport, evidencing efficient carrier injection across the vdW interface. Furthermore, a dopant-free complementary metal-oxide-semiconductor (CMOS) inverter is realized by integrating p-type NbSe₂ and n-type Sb contacts on WSe₂. These results establish metallic vdW contacts as an effective strategy to suppress FLP and enable high-performance 2D electronics.