Steep Slope p-type 2D WSe<inf>2</inf> Field-Effect Transistors with Van Der Waals Contact and Negative Capacitance

Steep-slope p-type 2D WSe 2 back-gated field-effect transistors (FETs) are realized by using van der Waals Pt-WSe 2 contact and HfZrO 2 / Al 2 O 3 as the dielectric layer. The van der Waals Pt-WSe 2 contact is free from disorder and Fermi level pinning and decreases the subthreshold slope. The WSe 2 NCFET with van der Waals contact shows low subthreshold slope for both forward and reverse gate voltage sweep (the minimum $\text{SS}_{\text{forward}}=18.2\ \text{mV}/\text{dec}$ and $\text{SS}_{\text{reverse}}=44.1\ \text{mV}/\text{dec}$ ) with a hysteresis as small as 20 mV at subthreshold region.