title: Chloride molecular doping technique on 2D materials: WS2 and MoS2.
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 kΩ·μm and 0.5 kΩ·μm, respectively. The significant reduction of the Rc is attributed to the achieved high electron-doping density, thus a significant reduction of Schottky barrier width. As a proof-of-concept, high-performance few-layer WS2 field-effect transistors (FETs) are demonstrated, exhibiting a high drain current of 380 μA/μm, an on/off ratio of 4 × 10(6), and a peak field-effect mobility of 60 cm(2)/(V·s). This doping technique provides a highly viable route to diminish the Rc in TMDs, paving the way for high-performance 2D nanoelectronic devices.
authors.affiliation: School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Lingming
authors.initials: L
authors.lastname: Yang
authors.forename: Kausik
authors.initials: K
authors.lastname: Majumdar
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Du
authors.forename: Heng
authors.initials: H
authors.lastname: Wu
authors.forename: Michael
authors.initials: M
authors.lastname: Hatzistergos
authors.forename: P Y
authors.initials: PY
authors.lastname: Hung
authors.forename: Robert
authors.initials: R
authors.lastname: Tieckelmann
authors.forename: Wilman
authors.initials: W
authors.lastname: Tsai
authors.forename: Chris
authors.initials: C
authors.lastname: Hobbs
authors.forename: Peide D
authors.initials: PD
authors.lastname: Ye
keywords: MoS2; Schottky barrier; TMDs; WS2; contact resistance; molecular doping