A hydrogen sensor, based on Toshiba's MEMS structure that employs palladium-based metallic glass, can consume less than 1% of conventional devices' power. The sensor can be fabricated on semiconductor manufacturing lines, allowing low-cost mass-production, according to the company.

Hydrogen-related technologies are paving the way for a low carbon hydrogen energy society. However, hydrogen is highly flammable, and leaks must be immediately detected. The battery-powered detectors that are used to do this must be capable of a rapid response to any leak, continual monitoring for long periods of time and consume very little power. Current sensors require a heater to sense hydrogen, pushing power consumption to the relatively high range of several tens of milliwatts to several watts. It is also necessary to use the heater frequently to reduce detection time, resulting a trade-off between detection time and power consumption.

Toshiba_hydrogen-sensor_01 (cr) Figure 1: Relation between response time and power consumption (Source: Toshiba)

Toshiba has developed an original MEMS structure with palladium-based metallic glass that realises both rapid detection and low power consumption. The sensor detects hydrogen at a power consumption level in the order of 100μW, less than 1% that of conventional devices, because it does not require continuous heating and adopts a capacitive-type MEMS structure.

Toshiba_hydrogen-sensor_02 (cr) Figure 2: Prototype hydrogen sensor and operation principles (Source: Toshiba)

Palladium is a well-known hydrogen storage material, but it takes time to combine with hydrogen, and requires heating for desorption. Adopting palladium-based metallic glass—an amorphous alloy—instead of palladium suppresses hydrogen bonding and enables a detection time of several seconds, similar to the time for conventional rapid-detection hydrogen sensors, according to Toshiba.

The developed sensor can be fabricated on semiconductor production lines and many sensors can be manufactured from one wafer, so low cost mass production is possible.

Toshiba_hydrogen-sensor_03 (cr) Figure 3: Hydrogen response characteristics of a prototype hydrogen sensor. (Source: Toshiba)