Towards NanoWatt-powered integrated CNT-NEMS sensors

Carbon nanotubes (CNTs) have been widely studied for their electrical, mechanical, and chemical properties since S. Iijima discovered them in 1991. After almost two decades, they are now steadily being recognized as a legitimate material to eventually replace silicon and metal based physical and chemical sensors. In this talk, we will present a semi-automatic process that has been effectively demonstrated in fabricating integrated CNT-based MEMS sensors, i.e., the process requires only ~1 sec to form a CNT sensing elements that could be further processed to develop integrated MEMS sensors. Examples of CNT devices fabricated with this technology include: (1) polymer MEMS pressure sensor using CNTs as sensing elements, (2) CNT anemometry flow sensor integrated in polymer microchannels, (3) CNT chemical sensors (e.g., alcohol vapor and chlorine sensors), (4) CNT-CMOS sensor, and (5) CNT thermal convective micro acceleration sensors. A very important factor for investigating CNTs as next generation sensing elements is that they may provide more than 10,000 times of reduction in activation power (i.e., CNT sensors may operate with 100 nW input) requirement than conventional MEMS sensors. Hence, CNT-based sensors may eventually advance technologies across several commercial sectors requiring low-power sensors, including mobile consumer electronics, distributed sensing networks, and embedded sensing for health-monitoring.