Hybrid piezoelectricity enabled flexible AZO/SiC thin films sensor with a high output voltage and broad temperature range

Abstract

There is an increasing attention on flexible sensors that can monitor pressure at high temperatures for emerging applications such as robotics, aerospace equipment and health monitoring. However, current flexible pressure sensors generally exhibit low working temperatures; therefore, it is urgent to develop sensitive and high-temperature reliable flexible sensors for harsh conditions. Herein, a highly sensitive, waterproof, high-temperature-resistant and flexible AZO/SiC hybrid thin-film sensor was proposed and fabricated for monitoring pressure on curved surfaces. The optimal sputtering time and target power yielded a superior AZO/SiC sensor with an ultrafast response time of 25.65 ms and a sensitivity of 9.22 mV kPa⁻¹, which is 65.83% higher than that of a single AZO film. The inherent flexibility of the sensor enabled a stable output voltage of 2 V at 180 °C, excellent waterproof performance and robust repeatability after 8000 cycles, which were superior to those of the sensors reported in previous studies. First-principles calculations revealed that the incorporation of SiC led to a marked reduction in band gap and enhanced the charge transfer in the AZO layer, resulting in superior conductivity and interfacial charge transfer capability. When attached to various parts of the human body, the flexible sensor exhibited a high output voltage and fast response time for recognizing body motions, demonstrating its real-time detection performance for monitoring human health.