A novel accelerometer based on contact resistance of integrated carbon nanotubes

A novel accelerometer based on electrical contact resistance change between two sets of carbon nanotubes (CNTs) is presented. After the micro structures are fabricated by silicon bulk micromachining, the CNTs are synthesized from each of the facing surfaces of proof-mass and fixed electrode. When the motion of the proof-mass is generated from incoming acceleration, effective contact area between two sets of CNT bundles changes, resulting in a change of electrical contact resistance. This CNTs-based accelerometer achieves both high sensitivity and wide bandwidth. Two different sensing modes are experimentally verified and compared: the approach mode where the incoming acceleration pushes the proof-mass to the fixed electrode and the separation mode where the acceleration pulls away the proof-mass from the fixed electrode. In each case, the sensitivities are 7.62 mV/g/V and 17.23 mV/g/V, respectively. It is confirmed that the contact resistance remained nearly constant after 14.4 million cycles of operation under 400 Hz sinusoidal acceleration with the magnitude of -10 g ~ +10 g.