Hydrogen Detection Using ZnO-Based Thin Film MEMS Integrated Sensor Chip

This work reports the development of a highly sensitive, selective hydrogen sensor chip utilizing ZnO-thin film integrated into the sensor platform along with an integrated microheater. The fabricated sensor chip is characterized and optimized to achieve a good sensor response to different exposed hydrogen concentrations in air. The selectivity check is studied in the presence of twelve other different interfering gases, i.e., Acetone, Ammonia, Carbon monoxide, Carbon dioxide, Ethelene, Ethyl alcohol, Hydrogen sulfide, Methane, Nitrogen oxide, Nitrogen dioxide, Oxygen, Sulfur dioxide, as these gases can affect the sensor performance in the indoor and outdoor application of hydrogen sensor. The repeatability check of sensor performance towards hydrogen detection is verified multiple times to understand the sensor response against each exposure of the interference gases. Moreover, a suitable combination of passive filters is used to improve the sensor performance further, which reduces the change of incoming air moisture around the sensor chip, improving the sensor's sensitivity towards the hydrogen gas. The main advantage of our sensor with the filter is that it can accurately detect hydrogen with interference gases at different RH conditions.