Ultrathin Tactile Sensors with Directional Sensitivity and a High Spatial Resolution

• Published in: Nano letters 2021-10, Vol.21 (19), p.8304-8310
• Main Authors: Dvořák, Nathan, Chung, Kunook, Mueller, Kobie, Ku, Pei-Cheng
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.1c02837

An ultrathin tactile sensor with directional sensitivity and capable of mapping at a high spatial resolution is proposed and demonstrated. Each sensor node consists of two gallium nitride (GaN) nanopillar light-emitting diodes. Shear stress applied on the nanopillars causes the electrons and holes to separate in the radial direction and reduces the light intensity emitted from the nanopillars. A sensor array comprising 64 sensor nodes was designed and fabricated. Two-dimensional directional sensitivity was experimentally confirmed with a dynamic range of 1–30 mN and an accuracy of ±1.3 mN. Tracking and mapping of an external force moving across the sensor array were also demonstrated. Finally, the proposed tactile sensor’s sensitivity was tested with a fingertip gently moving across the sensor array. The sensor successfully registered the finger movement’s direction and fingerprint pattern.