Individually addressable and flexible pressure sensor matrixes with ZnO nanotube arrays on graphene

We report the fabrication of individually addressable, high-density, vertical zinc oxide (ZnO) nanotube pressure sensor arrays. High-sensitivity and flexible piezoelectric sensors were fabricated using dimension- and position-controlled, vertical, and free-standing ZnO nanotubes on a graphene substrate. Significant pressure/force responses were achieved from small devices composed of only single, 3 x 3, 5 x 5, and 250 x 250 ZnO nanotube arrays on graphene. An individually addressable pixel matrix was fabricated by arranging the top and bottom electrodes of the sensors in a crossbar configuration. We investigated the uniformity and robustness of pressure/force spatial mapping by considering the pixel size, the number of ZnO nanotubes in each pixel, and the lateral dimensions of individual ZnO nanotubes. A spatial resolution as high as 1058 dpi was achieved for a Schottky diode-based force/pressure sensor composed of ZnO nanotubes on a flexible substrate. Additionally, we confirmed the excellent flexibility and electrical robustness of the free-standing sensor arrays for high-resolution tactile imaging. We believe that this work opens important opportunities for 1D piezoelectric pressure/force sensor arrays with enormous applications in human-electronics interfaces, smart skin, and micro- and nanoelectromechanical systems.

Automated summary

This study reports the fabrication of individually addressable, high-density, vertical zinc oxide nanotube pressure sensor arrays, and investigates their pressure/force response and spatial mapping. The results show significant pressure/force responses from small devices composed of ZnO nanotube arrays on graphene, and the achieved spatial resolution reaches 1058 dpi for Schottky diode-based force/pressure sensors. The flexibility and electrical robustness of the fabricated sensor arrays for high-resolution tactile imaging are also confirmed. This work opens important opportunities for the applications of 1D piezoelectric pressure/force sensor arrays in human-electronics interfaces, smart skin, and micro- and nanoelectromechanical systems.