Microacoustic Sensors with Integrated Carbon Nanotubes for High Voc Sensitivity

Electroacoustic resonators have proved to be appropriate candidates as VOC sensors owing to their high mass sensitivity. However, one of their drawbacks is their sensitivity to other external factors like the humidity. Here we propose an AlN-based solidly mounted resonator for VOC detection and humidity discrimination. This ability is achieved by defining different areas within the same device with different resonant characteristics by integrating carbon nanotubes (CNTs) in part of the exposed surface while leaving the other bare. While CNTs act as sensing elements adsorbing VOC molecules, hence originating larger frequency shifts, the bare zone is affected only by the ambient humidity.