High-Resolution Spatial Mapping of Pressure Distribution by a Flexible and Piezotronics Transistor Array

The simulation of human tactile through high-resolution electronics will play an essential role in robotics and human-robot interaction. Piezotronic tactile sensors can achieve a higher resolution of mapping and integration than conventional tactile sensors. Herein, we demonstrate a flexible tactile transistor sensing array based on piezotronic zinc oxide (ZnO) nanowires to modulate the carrier concentration directly. When a compressive strain is applied along the C-axis of the ZnO nanowire, positive piezoelectric charges will be induced at the channel to increase the concentration of electron carriers. With an applied pressure of 25 N, the current was increased more than 10 times. Moreover, the large-scale transistor array makes mapping of external forces possible. In this study, a flexible pressure sensor was designed with 181 dots per inch (DPI) pixel density. The pressure from a sapphire mold with a "BI" bump pattern was effectively mapped by the current changes of transistors. This study achieved spatially resolved pressure mapping, which has tremendous potential for applications in electronic skin, biomedicine, human-machine interfaces, and micro-nano sensing.