Lithography-Patterned Nafion Interlayers Enable High-Injection Contacts in p-MoTe2 FETs.

A lithography-compatible approach for site-selective contact engineering is developed by using electron-beam lithography to pattern ultrathin Nafion interlayers at the metal contacts of p-type MoTe2 field-effect transistors. The patterned Nafion films are prepared by electron-beam irradiation followed by development, forming conformal nanometer-thick layers localized exclusively at the source and drain regions. Due to its high work function, Nafion facilitates localized charge transfer that p-dopes the MoTe2 interface, thereby narrowing the Schottky barrier width for hole injection. Two-terminal and four-terminal electrical measurements allow a clear distinction between intrinsic channel properties and contact-related effects. Nafion-contacted devices show a 2-fold increase in on-state current, more linear output behavior, and field-effect mobility up to 10 cm2/V·s, compared to control devices with bare-Pt contacts. The convergence of two- and four-terminal mobilities observed in Nafion-modified transistors indicates the successful mitigation of contact resistance and Fermi-level pinning. An electron-beam dose of 10 μC cm-2 produces optimal results by achieving good pattern definition while maintaining effective interfacial doping. This site-selective patterning method offers a practical route for tailored contact engineering in 2D materials and represents a promising path toward improved p-type MoTe2 transistors for advanced electronic applications.