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.
@article{arxiv.1410.2563,
title = {Chloride Molecular Doping Technique on 2D Materials: WS2 and MoS2},
author = {Lingming Yang and Kausik Majumdar and Han Liu and Yuchen Du and Heng Wu and Michael Hatzistergos and P. Y. Hung and Robert Tieckelmann and Wilman Tsai and Chris Hobbs and Peide D. Ye},
journal= {arXiv preprint arXiv:1410.2563},
year = {2015}
}