Suspended CNT-FET piezoresistive strain gauges: Chirality assignment and quantitative analysis

Abstract

Carbon nanotubes can withstand large elastic deformation and show pronounced piezoresistive effects which make them promising candidates for low-power strain sensors in the large strain regime. Integration of individual suspended nanotubes into complex microelectromechanical devices, including gate structures, is still a challenge. Here, ultraclean carbon nanotubes spanning across actuated MEMS electrodes are operated as suspended Carbon Nanotube Field-Effect Transistors (CNT-FETs) under repeated variable strain up to 4.5%, thus acting as small-sized piezoresistive strain gauges whose gauge factor is electrostatically tuned by the gate. We present the first quantified electromechanical analysis of suspended CNT-FETs to uniaxial strain applied by on-chip micro actuators.