Microfabricated breath sensor based on carbon nanotubes for respiration monitoring

A microfabricated breath sensor based on multi-walled carbon nanotubes (MWCNTs) has been designed, developed and tested. This sensor has a simple capacitor structure, including a pair of metal electrodes fabricated by micromachining, which are then coated by a layer of carbon nanotubes. This structure takes advantage of the unique electrical property of MWCNTs in the small gap space as a function layer. It is indicated that the sensor has much higher sensitivity to the exhaled gas flow than that of bald electrodes structure with the same size. Meanwhile, the sensor can operate steadily with low supply voltage and energy consumption, avoiding ambient interference of flowing air. It also performs a remarkable response and recovery time, as well as more consistent to the exhaled gas flow. A hybrid mechanism is modeled preliminary as an explanation.