High-Quality P-type Contacts for Atomically Thin MoTe2 Transistors with High-Work-Function Semimetal TiS2 Electrodes

Abstract

High-performance p-type atomically thin transistors are fundamental components in CMOS-based digital logic circuits for beyond-silicon electronics. Compared with the recent breakthrough in high-quality semimetal contacts approaching the quantum limit on n-type atomically thin channel transistors, achieving high-performance p-type analogues with high-quality contacts remains challenging, which was mainly hindered by the lack of proper high-work-function metallic electrodes with Fermi level unpinning capacity. Herein, we demonstrate that semimetal TiS₂ electrodes prepared with a damage-free transfer process can be a feasible option for p-type atomically thin MoTe₂ transistors. Owing to its intrinsic large work function (∼5.3 eV) and high-quality contacts with negligible Schottky barrier at the TiS₂/MoTe₂ interface, the scaled p-type bilayer MoTe₂ transistor with 500 nm channel length and the monolayer transistor with 800 nm channel length exhibit a high on-state current (I_on) of 100 μA/μm with the on/off ratio (I_on/off) over 10⁶ and an I_on of 68 μA/μm with the I_on/off ratio over 10⁷, respectively. Such a demonstration will enable monolithic atomically thin MoTe₂-based beyond-silicon electronics via the common CMOS technology.