MEMS based hydrogen sensing with parts-per-billion resolution

This paper presents a microelectromechanical systems (MEMS) based hydrogen sensor utilizing a micro-cantilever (MC) functionalized with palladium, and an integrated silicon photonics based interferometric optical readout. The entire sensor is fabricated using standard surface micromachining processes, and the combined MEMS and optical readout allows extension to sensor-array implementations in the future. The sensor has a demonstrated capability of resolving a 38 ppb change in hydrogen concentration at room temperature and pressure, at an ambient background concentration of 50 ppm. This sensor platform provides a pathway towards realization of robust miniaturized devices for high precision monitoring of low-concentration hydrogen, as well as being suitable for future extension to multi-gas sensor-arrays.