Native Oxide MoO₂- MoSe₂ Heterostructure-Based Self-Powered Gas Sensor for Selective NO₂ and H₂ Detection.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Developing efficient and self-powered gas sensors is crucial for environmental monitoring and safety.
• Metal-semiconductor heterostructures offer unique properties for advanced sensing applications.

Purpose of the Study:

• To synthesize native oxide MoO₂-MoSe₂ heterostructure flakes using a single-step chemical vapor deposition (CVD) method.
• To investigate the gas sensing performance of these heterostructures for self-powered, room-temperature applications.

Main Methods:

• Single-step chemical vapor deposition (CVD) for heterostructure synthesis.
• Characterization using Raman, photoluminescence, AFM, XPS, UV-PES, TEM, and EDS.
• Gas sensing measurements under visible light and varying humidity.

Main Results:

• Two types of flakes (S1 and S2) with distinct compositions and interfaces were synthesized.
• Sample S1 showed selective H₂ detection, while S2 exhibited broadband photoresponse and high NO₂ sensitivity (10 ppm detection limit).
• Enhanced sensing performance was observed at low/zero bias, attributed to photocarriers and interface interactions, with humidity further boosting response.

Conclusions:

• Interface engineering of MoO₂-MoSe₂ heterostructures enables room-temperature, self-powered gas sensing.
• The developed sensors demonstrate high selectivity and sensitivity, suitable for humid environments.
• This approach paves the way for nanoelectronic and MEMS-integrable sensing devices.