Near-Ideal van der Waals NbSe<sub>2</sub> Contacts for WSe<sub>2</sub> CMOS Electronics.

Choi, Hyungyu; Song, Yunseo; Ali, Nasir; Shin, Hoseong; Yoon, Tae Woong; Jeong, Inhee; Park, Hyokwang; Song, Seunguk et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

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 NbSe<sub>2</sub> enable near-ideal p-type operation in WSe<sub>2</sub> field-effect transistors. Devices with NbSe<sub>2</sub> 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 NbSe<sub>2</sub> and n-type Sb contacts on WSe<sub>2</sub>. These results establish metallic vdW contacts as an effective strategy to suppress FLP and enable high-performance 2D electronics.