Monolayer MoS2 Nanoribbon Transistors Fabricated by Scanning Probe Lithography

• Published in: Nano letters Vol. 19; no. 3; pp. 2092 - 2098
• Main Authors: Chen, Sihan, Kim, SunPhil, Chen, Weibing, Yuan, Jiangtan, Bashir, Rashid, Lou, Jun, van der Zande, Arend M, King, William P
• Format: Journal Article
• Language: English
• Published: American Chemical Society 13.03.2019
• Subjects: narrow channel; monolayer; MoS2 transistor; scanning probe lithography
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.9b00271

Monolayer MoS2 is a promising material for nanoelectronics; however, the lack of nanofabrication tools and processes has made it very challenging to realize nanometer-scale electronic devices from monolayer MoS2. Here, we demonstrate the fabrication of monolayer MoS2 nanoribbon field-effect transistors as narrow as 30 nm using scanning probe lithography (SPL). The SPL process uses a heated nanometer-scale tip to deposit narrow nanoribbon polymer structures onto monolayer MoS2. The polymer serves as an etch mask during a XeF2 vapor etch, which defines the channel of a field-effect transistor (FET). We fabricated seven devices with a channel width ranging from 30 to 370 nm, and the fabrication process was carefully studied by electronic measurements made at each process step. The nanoribbon devices have a current on/off ratio > 104 and an extrinsic field-effect mobility up to 8.53 cm2/(V s). By comparing a 30 nm wide device with a 60 nm wide device that was fabricated on the same MoS2 flake, we found the narrower device had a smaller mobility, a lower on/off ratio, and a larger subthreshold swing. To our knowledge, this is the first published work that describes a working transistor device from monolayer MoS2 with a channel width smaller than 100 nm.