Low voltage and high ON/OFF ratio field-effect transistors based on CVD MoS2 and ultra high-k gate dielectric PZT

Abstract

MoS₂ and other atomic-level thick layered materials have been shown to have a high potential for outperforming Si transistors at the scaling limit. In this work, we demonstrate a MoS₂ transistor with a low voltage and high ON/OFF ratio. A record small equivalent oxide thickness of ∼1.1 nm has been obtained by using ultra high-k gate dielectric Pb(Zr_0.52Ti_0.48)O₃. The low threshold voltage (<0.5 V) is comparable to that of the liquid/gel gated MoS₂ transistor. The small sub-threshold swing of 85.9 mV dec⁻¹, the high ON/OFF ratio of ∼10⁸ and the negligible hysteresis ensure a high performance of the MoS₂ transistor operating at 1 V. The extracted field-effect mobility of 1–10 cm² V⁻¹ s⁻¹ suggests a high crystalline quality of the CVD-grown MoS₂ flakes. The combination of the two-dimensional layered semiconductor and the ultra high-k dielectric may enable the development of low-power electronic applications.