Heterointerface-Induced Charge Transfer Kinetics in Sputtered MoTe₂-MoS₂ Nanocomposite for High-Performance Ambient...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Development of sensitive and selective gas sensors is crucial for environmental monitoring and safety.
• Room-temperature gas sensing remains a challenge, often requiring elevated temperatures for optimal performance.
• Molybdenum disulfide (MoS2) and molybdenum ditelluride (MoTe2) are promising 2D materials for electronic applications, including gas sensing.

Purpose of the Study:

• To develop and characterize a nanostructured MoTe2-MoS2 n-n heterojunction gas sensor on a silicon substrate.
• To demonstrate room-temperature sensing of nitrogen dioxide (NO2).
• To investigate the sensing mechanism based on heterointerface band modulation and defect-assisted adsorption.

Main Methods:

• Fabrication of a MoTe2-MoS2 nanocomposite thin film using one-step magnetron co-sputtering on a Si substrate.
• Surface analysis and structural characterization to determine morphology and defect sites.
• Gas sensing performance evaluation at room temperature, including response, recovery time, selectivity, and detection limit.

Main Results:

• The MoTe2-MoS2/Si sensor exhibited a porous, defect-rich morphology with abundant active sites.
• Exceptional sensor response (74.4%) and ultrafast response/recovery times (7.5/2 s) for 25 ppm NO2 at room temperature (30 °C).
• High reproducibility, consistency across a wide concentration range (1-60 ppm), remarkable selectivity, and a low detection limit (700 ppb).

Conclusions:

• The nanostructured MoTe2-MoS2 heterojunction is a highly effective platform for room-temperature NO2 sensing.
• The enhanced sensing performance is attributed to the unique heterointerface properties and defect-rich surface.
• This research provides a foundation for developing advanced, high-performance NO2 gas sensors.