A graphene-based MEMS binary sensor for hydrogen detection

Micro/Nano gas sensors can accurately detect mass variations on the order of a few nano to atto-grams. They are increasingly being used as chemical and biological sensors after being equipped with a functional material to selectively immobilize a particular gas, protein, or organism from a fluid pool or stream. The development of these sensors requires ways to overcome many challenges, including functional material stability and selectivity and overall sensor detection range, response time, hysteresis, and cost. Developing better mass sensors will help address problems of sensitivity, reliability, and cost effectiveness in this new generation of chemical and biological micro sensors. MEMS sensors are generally categorized according to their actuation state into static and dynamic sensors. In this project, we focus on static sensing. Static sensors measure the deflection of the sensor as a means of detecting a specific gas concentration. It is based on a sensing mechanism for electrostatic MEMS that employs the static pull-in phenomenon which results in binary detection. Since pull-in is an instability, the sensitivity of the MEMS sensor represents an upper bound on the sensitivity of static sensors. The sensor employs a plate supported by a micro cantilever beam over an underlying fixed electrode, and it is implemented as a hydrogen sensor. The main focus of this study is to develop an efficient mathematical model for MEMS sensors equipped with a graphene layer and evaluate the sensitivity of the sensor for hydrogen detection. It is worth noting that the development of such advanced graphene-based MEMS sensors holds a great potential for industry in Saudi Arabia, especially for oil and gas industries.