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

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Contact resistance significantly hinders the performance of 2D material-based transistors.
• Efficient charge injection is crucial for optimizing field-effect transistor (FET) characteristics.
• Developing site-selective methods for contact engineering is essential for advanced electronic devices.

Purpose of the Study:

• To develop a lithography-compatible method for site-selective contact engineering in p-type MoTe2 FETs.
• To investigate the impact of ultrathin Nafion interlayers on charge injection and device performance.
• To mitigate contact resistance and Fermi-level pinning in MoTe2 transistors.

Main Methods:

• Site-selective patterning of ultrathin Nafion interlayers using electron-beam lithography.
• Fabrication of p-type MoTe2 field-effect transistors with patterned Nafion at source/drain contacts.
• Electrical characterization using two-terminal and four-terminal measurements.

Main Results:

• Nafion interlayers facilitated localized charge transfer, p-doping the MoTe2 interface and narrowing the Schottky barrier.
• Nafion-contacted devices exhibited a 2-fold increase in on-state current and more linear output.
• Field-effect mobility improved up to 10 cm²/V·s, with convergence of two- and four-terminal mobilities indicating reduced contact resistance.

Conclusions:

• Site-selective patterning of Nafion via electron-beam lithography is a practical approach for contact engineering in 2D materials.
• This method effectively reduces contact resistance and Fermi-level pinning in p-type MoTe2 transistors.
• The developed technique offers a promising route toward improved MoTe2-based electronic devices.