Junctionless Electric-Double-Layer MoS₂ Field-Effect Transistor with a Sub-5 nm Thick Electrostatically Highly Doped...

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Junctionless transistors offer advantages for sub-3 nm applications due to their simple structure and high performance.
• Two-dimensional transition-metal dichalcogenide materials like MoS₂ present potential solutions for silicon-based technology limitations.

Purpose of the Study:

• To present the first junctionless electric-double-layer field-effect transistor (JLFET) utilizing an electrostatically doped 5 nm thick MoS₂ channel.
• To investigate the electrical characteristics and operational mechanisms of this novel MoS₂ JLFET.

Main Methods:

• Fabrication of a double-gated MoS₂ transistor with an ionic-liquid top gate and a conventional bottom gate.
• Characterization of transfer characteristics, subthreshold swing, and drain-current behavior under varying gate biases.
• Analysis using numerical simulations and analytical models to elucidate device operation.

Main Results:

• The MoS₂ JLFET exhibited a high on-off current ratio of 10⁴ and a subthreshold swing of 70 mV dec^-1 at 0 V bottom-gate bias.
• Significant leftward shift in transfer characteristics with increasing bottom-gate bias, attributed to enhanced carrier concentration.
• Observed features in transconductance and its derivative at high bottom-gate bias, consistent with silicon-based JLFETs, and reduced electron mobility degradation.

Conclusions:

• The developed MoS₂ JLFET demonstrates excellent performance and characteristics suitable for advanced electronic applications.
• The study clarifies the operational principles of junctionless MoS₂ transistors with electrostatically doped channels.
• This research paves the way for next-generation electronics beyond silicon technology.