A sensitive, robust, high temperature resistant flexible piezoelectric sensor based on SiC/AlN hybrid thin films

Abstract

Flexible pressure sensors generate significant attention for their promising applications in wearable electronic devices and human-computer interaction systems. Specially, high-temperature resistant flexible sensors are urgently demanded to detect physiological characteristics of human such as firefighters and deep-sea workers in harsh environments. In this study, a highly sensitive, waterproof, high-temperature resistant flexible silicon carbide (SiC)/aluminum nitride (AlN) sensor is proposed, and prepared by magnetron sputtering hybrid piezoelectric thin-film on silica gel substrate. The SiC/AlN thin-film sensor exhibits a high sensitivity of 7.44 mV/kPa and high R² value of 0.9159 at a pressure below 150 kPa, together with improved piezoelectric performance of 52.27% compared to that of SiC sensor. In addition, the flexible piezoelectric sensor can practically recognize human motions of sitting to standing, walking and running and shows excellent reliability upon 4000 cycling loading. The SiC/AlN sensor also exhibits high sensitivity of 3.358 mV/kPa at high temperatures and presents excellent stability up to 170°C. First-principles calculations suggest that the incorporation of AlN significantly reduces band gap of SiC, with enhanced charge transport and improved carrier transport efficiency. This work provides an experimental and numerical perspective for designing high performance, low-cost flexible sensors for harsh environments.