Steep Slope p-type 2D WSe2 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.