Self-powered and flexible piezo-sensors based on conductivity-controlled GaN nanowire-arrays for mimicking rapid- and slow-adapting mechanoreceptors

Abstract

Human skin contains slowly adaptive (SA) and rapidly adaptive (RA) mechanoreceptors, which respond differently to external stimuli. Based on human tactile perception principles, the fabrication of a self-powered electronic skin (e-skin) that simultaneously mimics SA- and RA-mechanoreceptors is a prime need for robots and artificial prosthetics to interact with the surrounding environment. However, the complex process of merging multimode sensors to mimic SA- and RA-mechanoreceptors hinders their utilization in e-skins. We proposed SA- and RA-mechanoreceptors based on n-type and semi-insulating GaN nanowire arrays. The SA- and RA-mechanoreceptors demonstrated distinguished features such as grasping of objects and detection of their surface textures. Based on piezoelectric sensing principles, the proposed e-skin can simultaneously mimic static and dynamic pressure signals. Mechanoreceptors further detected several stimuli of various pressures with low and high frequencies. The response and reset times showed by SA-mechanoreceptors were 11 and 18 ms under 1-Hz frequency, which are rapid enough for practical e-skin applications.