Airborne engineered nanoparticle mass sensor based on a silicon resonant cantilever

A silicon resonant cantilever sensor is developed for detection of airborne nanoparticles (NPs) by monitoring the change in resonant frequency induced by an additional mass of trapped NPs. A piezoelectric stack actuator and a piezoresistive strain gauge are involved in the sensor system in order to actuate and detect the oscillation of cantilever sensor, respectively. An electrostatic precipitator is employed to trap the NPs on the cantilever surface. The proposed sensor reveals a mass sensitivity of 10 Hz/ng and a quality factor of 1206 while operated in the fundamental flexural mode. As necessary for an application under workplace conditions the limitations of the sensor sensitivity imposed by the environment are investigated, i.e., the influences of temperature, relative humidity, and pressure on the sensor are measured.