Using confined self-adjusting carbon nanotube arrays as high-sensitivity displacement sensing element

Displacement sensing is a fundamental process in mechanical sensors such as force sensors, pressure sensors, accelerometers, and gyroscopes. Advanced techniques utilizing nanomaterials have attracted considerable attention in the drive to enhance the process. In this paper, we propose a novel and highly sensitive device for detecting small displacements. The device utilizes the changes in contact resistance between two sets of vertically aligned carbon nanotube (CNT) arrays, the growth of which was confined to enable their facile and reliable integration with fully fabricated microstructures. Using the displacement transduction of the proposed device, we successfully demonstrated a 3-axis wide bandwidth accelerometer, which was experimentally confirmed to be highly sensitive compared to conventional piezoresistive sensors. Through a test involving 1.2 million cycles of displacement transductions, the contact resistance of the CNT arrays was proved to be excellently stable, which was a consequence of the high electrical stability and mechanical durability of the CNTs.