Selective laser-induced etching process-enabled double-cavity glass MEMS hydrogen sensor at room-temperature...

Area of Science:

• Materials Science
• Microelectromechanical Systems (MEMS)
• Chemical Sensing

Background:

• Hydrogen sensors are crucial for safety and energy applications.
• Existing sensors often face limitations in sensitivity, operating temperature, and scalability.
• MEMS technology offers miniaturization and integration potential for sensor development.

Purpose of the Study:

• To develop a high-performance, room-temperature hydrogen sensor using a novel glass-based MEMS platform.
• To enhance sensor sensitivity and thermal stability through innovative cavity engineering and catalyst design.
• To establish a scalable and cost-effective manufacturing process for microsystem hydrogen sensing.

Main Methods:

• Fabrication of a single glass wafer with high-aspect-ratio vias and double cavities using laser-induced selective wet etching.
• Integration of a suspended sensing membrane with platinum interdigital electrodes and platinum/nitrogen-doped carbon sphere (NCS) catalyst islands.
• Utilizing pyridinic/pyrrolic nitrogen sites on NCS to promote H2 dissociation and spillover for chemiresistive transduction.
• Employing finite-element simulations and infrared thermography to analyze thermal performance.

Main Results:

• The glass-based MEMS sensor demonstrated enhanced thermal stability, maintaining the sensing region ~10°C higher than planar devices.
• A significant, order-of-magnitude (~10 times) increase in sensitivity at room temperature was achieved.
• The nitrogen-doped carbon spheres (NCS) with platinum catalyst effectively facilitated hydrogen dissociation and spillover.
• The simplified, bonding-free single glass wafer process proved scalable and economical.

Conclusions:

• The developed glass-based MEMS hydrogen sensor offers a high-performance, room-temperature sensing solution.
• The combination of cavity engineering and Pt/NCS catalyst significantly boosts sensor sensitivity and thermal management.
• This platform provides a scalable, economical, and reliable foundation for advanced microsystem hydrogen sensing applications.