Tunnel Thin-Film Transistors for Ultralow-Power and High-Performance Flexible Electronics

Area of Science:

• Materials Science
• Electronics Engineering
• Quantum Physics

Background:

• Thin-film transistors (TFTs) are essential for large-area electronics but limited by the thermionic limit (≈60 mV dec⁻¹ SS).
• This limit hinders the development of low-power flexible electronics for applications like wearable sensors.
• Overcoming this bottleneck is crucial for advancing flexible electronic technologies.

Purpose of the Study:

• To introduce flexible tunnel TFTs that harness quantum band-to-band tunneling.
• To demonstrate that these devices can surpass the conventional thermionic limit.
• To showcase the fabrication and performance of flexible electronic circuits using these novel TFTs.

Main Methods:

• Fabrication of flexible tunnel TFTs on ultrathin (6 µm) flexible substrates.
• Utilizing quantum band-to-band tunneling to achieve subthreshold swing below the thermionic limit.
• Employing a protective layer-assisted photolithography method for fabricating complex circuits.

Main Results:

• Achieved subthermionic SS of 28.8 mV dec⁻¹ with a large intrinsic gain (≈10⁴) at 1 V operating voltage.
• Successfully fabricated flexible tunnel TFT active-matrix arrays, amplifiers, and logic circuits.
• Demonstrated robust mechanical flexibility (bendable to 50 µm radius) and high-performance amplification (1000 V/V gain) for electromyography signal acquisition (77 dB SNR).
• Logic circuits operated with picowatt-level power consumption.

Conclusions:

• Flexible tunnel TFTs successfully transcend the thermionic limit, offering a new device concept for energy-efficient flexible electronics.
• The demonstrated subthermionic performance and flexibility pave the way for advanced applications in wearable and flexible systems.
• This breakthrough enables high-performance, low-power flexible electronic devices with enhanced durability.