Growth of Wide-Bandgap Monolayer Molybdenum Disulfide for a Highly Sensitive Micro-Displacement Sensor

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Physics

Background:

• Two-dimensional (2D) piezoelectric semiconductor materials are crucial for intelligent sensing and energy harvesting.
• Molybdenum disulfide (MoS2), a 2D wide-bandgap semiconductor, exhibits piezoelectricity in odd-layered structures due to its lack of an inversion symmetry center.

Purpose of the Study:

• To synthesize monolayer MoS2 using chemical vapor deposition (CVD).
• To fabricate a novel micro-displacement sensor based on MoS2 for strain detection.

Main Methods:

• Synthesized monolayer MoS2 (approximately 50 µm lateral size) on Si/SiO2 via CVD.
• Confirmed non-centrosymmetric crystal structure using second-harmonic generation (SHG) characterization.
• Fabricated a MoS2-based micro-displacement sensor on a flexible polyethylene terephthalate (PET) substrate using maskless lithography and hot evaporation.

Main Results:

• Achieved a piezoelectric response current of 5.12 nA under 0.003% strain along the armchair direction.
• Demonstrated a near-linear relationship between piezoelectric response current and strain (40-100 µm displacement).
• Calculated a response sensitivity of 1.154 µA/%.

Conclusions:

• Successfully developed a novel MoS2-based micro-displacement sensor with significant piezoelectric properties.
• The sensor shows potential for advanced surface texture sensing applications.
• Highlights the utility of 2D piezoelectric materials in next-generation sensing technologies.