Gas Sensor Technology
Miniature Metal Oxide Semiconductor based sensing of gases and VOCs
In short
Metal oxide (MOS) gas sensors are devices that detect gases in the air by measuring changes in electrical resistance of a metal oxide material when it interacts with gas molecules. They are widely used for detecting gases like CO, NO₂, NH₃, H₂, and VOCs (volatile organic compounds).
The MSGS is a SnO2 based MOS gas sensor which operate best at high temperatures (150–400 °C), depending on the metal oxide and target gas.
Advantages
- Simple and inexpensive.
- High sensitivity to many gases.
- Long lifetime.
- Small size, can be miniaturized.
In detail
How metal-oxide gas sensors work
The measurement of specific oxidizing or reducing gases is based on a reversible conductivity change of the sensing element at an appropriate working temperature. Controlling high temperatures accurately is critical for performance, and is typically achieved using micro-hot plates.
A typical MOS sensor contains:
- Sensing layer: Thin film of metal oxide.
- Electrodes: To measure resistance changes.
- Heater: Maintains the metal oxide at an optimal temperature.
- Substrate: Supports the structure and may isolate the heater electrically.
The MSGS driver electronics allows the control of the micro-hot-plate’s power and thus the sensor’s temperature. Through the modulation of the sensor temperature, the selectivity of the MSGS can be moderately tuned towards a selected gas.
Application
Gas detection for smart and industrial systems
- Indoor air quality monitoring
- VOC detection in buildings and vehicles
- Environmental and safety sensing
- Industrial leak detection
- Smart home and IoT devices
- Automotive exhaust and gas control
