Multifunctional WS₂-Au Field-Effect Transistors with Asymmetrical Contact for High Self-Driven Photoresponsivity and...

Area of Science:

• Materials Science
• Nanotechnology
• Electronics

Background:

• The growing need for self-driven, multifunctional devices in the Internet of Things (IoT) and wearable technology sectors demands innovative integration strategies.
• Tungsten disulfide (WS2), a material with tunable optoelectronic properties, presents a promising candidate for addressing these integration challenges.

Purpose of the Study:

• To engineer asymmetric contacts in WS2 field-effect transistors (FETs) to achieve distinct self-driven behaviors.
• To explore the potential of these engineered transistors for applications in environmental monitoring and adaptive optoelectronics.

Main Methods:

• Fabrication of WS2 field-effect transistors (FETs) with engineered asymmetric contacts.
• Characterization of the optoelectronic properties and gas sensing capabilities of both lower-asymmetry transistors (LAT) and higher-asymmetry transistors (HAT).
• Testing the performance of flexible devices under mechanical strain to assess wearability.

Main Results:

• The lower-asymmetry transistor (LAT) demonstrated a nonlinear photoresponse with enhanced n-type photocurrent under 470 nm laser illumination.
• The higher-asymmetry transistor (HAT) exhibited gate-tunable ambipolar photoresponse and ultrahigh NO2 sensitivity (94.4% at 2.8 ppm), albeit with a limited dynamic range.
• The LAT achieved high sensitivity (96.6% at 8.4 ppm) with ppb-level NO2 detection (100 ppb limit) and a Langmuir-type monotonic response.
• Flexible WS2 devices on PET substrates maintained robust gas response under mechanical strain, confirming wearability.

Conclusions:

• Asymmetric contact engineering in WS2 FETs is an effective strategy for achieving distinct self-driven behaviors.
• These devices offer a promising framework for developing energy-efficient, miniaturized systems for environmental monitoring and adaptive optoelectronics.
• The study highlights the potential of WS2-based transistors for next-generation wearable and IoT applications.