July 14th, 2015

Iranian researchers designed a sensor with the capability of rapidly detecting the amount of hydrogen existing in the environment.

This sensor can detect the leak of hydrogen in hazardous environment which can prevent the explosion.

Hydrogen sensors are convertors that create electrical signal by adsorbing hydrogen molecules, which depends on the concentration of the hydrogen. In this research, a capacitor MOS sensor was produced that detects the leak of hydrogen at explosive level (4 vol. percent) in less than two minutes. Capacitor sensors detect any change in the environment through changing the electrical capacity of the capacitor. The advantages of these sensors over other types of sensors are stability, long lifetime and low response time.

There is a need for high speed and accuracy to monitor and control hydrogen concentration in various fields of industry. For instance, this sensor can be used in the monitoring of hydrogen concentration during the production of ammonia, methanol and hydration of hydrocarbons. Among other applications of this sensor, mention can be made of desulfurization of petroleum products, production of jet fuel and launching of aircrafts and other aerospace applications.

This research also studies the effect of the thickness of oxide layers in the sensor structure on its properties and performance. Based on the results, the sensor detects hydrogen in a shorter period of time as the thickness of oxide layer decreases. Response time has been calculated to be 84 seconds for a capacitor sensor with oxide layer thickness of 28 nanometers.