Radio Frequency Transistors and Circuits Based on CVD MoS2.

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Molybdenum disulfide (MoS2) is a promising 2D material for next-generation electronics.
• Chemical vapor deposition (CVD) enables large-area synthesis of high-quality MoS2 films.
• Understanding the radio frequency (RF) performance of MoS2 transistors is crucial for high-speed applications.

Purpose of the Study:

• To investigate the gigahertz RF performance of CVD-grown monolayer MoS2 field-effect transistors (FETs).
• To evaluate the suitability of MoS2 for analog circuit applications.
• To demonstrate basic analog circuit functionalities using MoS2 FETs.

Main Methods:

• Fabrication of MoS2 FETs using CVD-grown monolayer MoS2.
• DC characterization to determine key transistor parameters (current density, transconductance, mobility).
• RF characterization using ground-signal-ground (GSG) layout and de-embedding techniques to measure cutoff frequencies (fT, fmax).
• Demonstration of amplifier and mixer circuits.

Main Results:

• Achieved high current densities (>200 μA/μm) and transconductance (38 μS/μm).
• Obtained a contact resistance-corrected mobility of 55 cm²/Vs.
• Measured fT of 6.7 GHz and fmax of 5.3 GHz for 250 nm gate length devices.
• Demonstrated extrinsic voltage gain (Av) of 6 dB at 100 MHz, with amplification up to 3 GHz.
• Successfully implemented a common-source amplifier with 14 dB gain and a frequency mixer with -15 dB conversion gain.

Conclusions:

• CVD monolayer MoS2 FETs exhibit promising gigahertz RF performance.
• The demonstrated analog circuit functionalities indicate MoS2's potential for electronic applications.
• Large-area CVD MoS2 is suitable for industrial-scale electronic device fabrication.