TiO₂-modified MoS₂ monolayer films enable sensitive NH₃ sensing at room temperature

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• High-performance ammonia (NH3) sensors are crucial for environmental monitoring and disease diagnosis.
• Two-dimensional (2D) molybdenum disulfide (MoS2) shows promise for room-temperature (RT) NH3 sensors but lacks sufficient sensitivity.

Purpose of the Study:

• To enhance the room-temperature NH3 sensing performance of MoS2.
• To investigate the effect of TiO2 modification on MoS2-based NH3 sensors.

Main Methods:

• Fabrication of TiO2-modified monolayer MoS2 films with controlled TiO2 loading.
• Utilized n-n hetero-compositing strategy for TiO2/MoS2 system.
• Characterization using in situ Kelvin potential force microscopy.

Main Results:

• Remarkable enhancement in RT NH3 sensing performance observed in TiO2/MoS2 system.
• Device with 95% TiO2 surface coverage demonstrated superior sensor response, low detection limit (0.5 ppm), wide detection range (0.5-1000 ppm), good repeatability, and selectivity.
• TiO2 modification improved surface reactivity and acted as 'gas-gating' layers, modulating MoS2 conductivity.

Conclusions:

• TiO2 modification effectively boosts the NH3 sensing capabilities of MoS2-based sensors.
• The n-n hetero-compositing strategy provides a simple and cost-effective method for developing high-performance 2D semiconductor sensors.
• This approach holds significant potential for advancing environmental and diagnostic sensing technologies.