Chloride Molecular Doping Technique on 2D Materials: WS2 and MoS2

TL;DR

This paper introduces a chloride molecular doping method that significantly reduces contact resistance in WS2 and MoS2 2D materials, enabling high-performance transistors with improved electrical characteristics.

Contribution

The study presents a novel chloride molecular doping technique that effectively lowers contact resistance in TMDs, enhancing their suitability for nano-electronic devices.

Findings

Reduced Rc to 0.7 kohm*um in WS2 and 0.5 kohm*um in MoS2

Achieved high drain current of 380 uA/um in FETs

Demonstrated high on/off ratio of 4×10^6

Abstract

Low-resistivity metal-semiconductor (M-S) contact is one of the urgent challenges in the research of 2D transition metal dichalcogenides (TMDs). Here, we report a chloride molecular doping technique which greatly reduces the contact resistance (Rc) in the few-layer WS2 and MoS2. After doping, the Rc of WS2 and MoS2 have been decreased to 0.7 kohm*um and 0.5 kohm*um, respectively. The significant reduction of the Rc is attributed to the achieved high electron doping density thus significant reduction of Schottky barrier width. As a proof-ofconcept, high-performance few-layer WS2 field-effect transistors (FETs) are demonstrated, exhibiting a high drain current of 380 uA/um, an on/off ratio of 4*106, and a peak field-effect mobility of 60 cm2/V*s. This doping technique provides a highly viable route to diminish the Rc in TMDs, paving the way for high-performance 2D nano-electronic devices.